{"id":4580,"date":"2026-10-17T18:14:52","date_gmt":"2026-10-17T18:14:52","guid":{"rendered":"https:\/\/huyuglobal.com\/?p=4580"},"modified":"2026-10-17T18:14:53","modified_gmt":"2026-10-17T18:14:53","slug":"14-gauge-wire-amp-rating","status":"publish","type":"post","link":"https:\/\/huyuglobal.com\/vi\/blog\/14-gauge-wire-amp-rating\/","title":{"rendered":"\u0110\u00e1nh gi\u00e1 Amp c\u1ee7a D\u00e2y 14 Gauge: 15 Amps, 20 Amps, hay 25?"},"content":{"rendered":"<p>Khi b\u1ea1n h\u1ecfi b\u1ea5t k\u1ef3 ba th\u1ee3 \u0111i\u1ec7n n\u00e0o v\u1ec1 ampacity c\u1ee7a d\u00e2y 14 gauge, b\u1ea1n s\u1ebd nghe ba c\u00e2u tr\u1ea3 l\u1eddi h\u1ee3p l\u1ec7 v\u1ec1 m\u1eb7t k\u1ef9 thu\u1eadt: 15, 20 ho\u1eb7c 25 ampe. V\u1ec1 m\u1eb7t b\u1ea3ng m\u00e3, c\u1ea3 hai nh\u00f3m \u0111\u1ec1u d\u1ef1a tr\u00ean c\u00f9ng m\u1ed9t b\u1ed9 d\u1eef li\u1ec7u. S\u1ef1 kh\u00e1c bi\u1ec7t quan tr\u1ecdng l\u00e0 quy \u0111\u1ecbnh n\u00e0o \u00e1p d\u1ee5ng cho m\u1ea1ch b\u1ea1n \u0111ang x\u1eed l\u00fd. Trong tr\u01b0\u1eddng h\u1ee3p d\u00e2y 14 AWG, \u0111i\u1ec1u n\u00e0y c\u00f3 th\u1ec3 l\u00e0m cho n\u00f3 tr\u1edf th\u00e0nh k\u00edch th\u01b0\u1edbc d\u00e2y quan tr\u1ecdng nh\u1ea5t, v\u00ec c\u00f3 m\u1ed9t ph\u1ea7n c\u1ee5 th\u1ec3 c\u1ee7a m\u00e3 quy \u0111\u1ecbnh ghi \u0111\u00e8 ho\u00e0n to\u00e0n c\u00e1c b\u1ea3ng ampacity.<\/p>\n<blockquote><p>T\u00f3m l\u1ea1i, theo B\u1ea3ng NEC 310.16, d\u00e2y \u0111\u1ed3ng 14 AWG \u0111\u01b0\u1ee3c \u0111\u00e1nh gi\u00e1 \u1edf 60 \u0111\u1ed9 C c\u00f3 ampacity l\u00e0 15A, \u1edf 75 \u0111\u1ed9 C ampacity t\u0103ng l\u00ean 20A v\u00e0 \u1edf 90 \u0111\u1ed9 C t\u0103ng l\u00ean t\u1ed1i \u0111a 25A. Tuy nhi\u00ean, s\u1eed d\u1ee5ng NEC 240.4D, c\u00f3 th\u1ec3 th\u1ea5y r\u1eb1ng d\u00e2y \u0111\u1ed3ng 14 AWG b\u1ecb gi\u1edbi h\u1ea1n d\u00f2ng \u0111i\u1ec7n \u1edf m\u1ee9c 15 b\u1ea5t k\u1ec3 x\u1ebfp h\u1ea1ng c\u00e1ch \u0111i\u1ec7n. Do gi\u1edbi h\u1ea1n n\u00e0y, d\u00e2y \u0111\u1ed3ng 14 AWG ch\u1ec9 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho m\u1ea1ch chi\u1ebfu s\u00e1ng v\u00e0 \u1ed5 c\u1eafm. Ngo\u00e0i ra, c\u1ea7n l\u01b0u \u00fd r\u1eb1ng kh\u00f4ng c\u00f3 d\u00e2y nh\u00f4m n\u00e0o c\u00f3 k\u00edch th\u01b0\u1edbc n\u00e0y d\u00e0nh cho d\u00e2y nh\u00e1nh.<\/p><\/blockquote>\n<h2>14 AWG Th\u1ef1c Ch\u1ea5t L\u00e0 G\u00ec<\/h2>\n<p>American Wire Gauge l\u00e0 h\u1ec7 th\u1ed1ng \u0111\u1ea3o ng\u01b0\u1ee3c \u2014 trong h\u1ec7 th\u1ed1ng n\u00e0y, s\u1ed1 nh\u1ecf h\u01a1n bi\u1ec3u th\u1ecb d\u00e2y l\u1edbn h\u01a1n. K\u00edch th\u01b0\u1edbc nh\u1ecf nh\u1ea5t th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho d\u00e2y c\u1ed1 \u0111\u1ecbnh \u1edf B\u1eafc M\u1ef9 l\u00e0 14 AWG, nh\u1ecf h\u01a1n m\u1ed9t k\u00edch th\u01b0\u1edbc so v\u1edbi 12 AWG v\u00e0 nh\u1ecf h\u01a1n hai k\u00edch th\u01b0\u1edbc so v\u1edbi 10 AWG.<\/p>\n<table>\n<tbody>\n<tr>\n<th>Thu\u1ed9c t\u00ednh<\/th>\n<th>Gi\u00e1 tr\u1ecb<\/th>\n<\/tr>\n<tr>\n<td>Di\u1ec7n t\u00edch m\u1eb7t c\u1eaft ngang<\/td>\n<td>110 mil tr\u00f2n (kho\u1ea3ng 2,08 mm\u00b2)<\/td>\n<\/tr>\n<tr>\n<td>\u0110i\u1ec7n tr\u1edf DC, \u0111\u1ed3ng<\/td>\n<td>3,07 \u03a9 tr\u00ean 1.000 ft<\/td>\n<\/tr>\n<tr>\n<td>\u0110i\u1ec7n tr\u1edf DC, nh\u00f4m<\/td>\n<td>5,06 \u03a9 tr\u00ean 1.000 ft (n\u1ebfu c\u00f3)<\/td>\n<\/tr>\n<tr>\n<td>C\u00e1ch \u0111i\u1ec7n \u0111i\u1ec3n h\u00ecnh<\/td>\n<td>V\u1ecf NM-B, d\u00e2y \u0111\u01a1n THHN\/THWN-2, d\u00e2y \u0111\u00e8n<\/td>\n<\/tr>\n<tr>\n<td>B\u1ed9 ng\u1eaft m\u1ea1ch \u0111i\u1ec3n h\u00ecnh<\/td>\n<td>15 A<\/td>\n<\/tr>\n<tr>\n<td>\u1ee8ng d\u1ee5ng \u0111i\u1ec3n h\u00ecnh<\/td>\n<td>M\u1ea1ch chi\u1ebfu s\u00e1ng, \u1ed5 c\u1eafm \u0111a n\u0103ng, d\u00e2y c\u00f4ng t\u1eafc<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>D\u00e2y \u0111i\u1ec7n tr\u1edf l\u00e0 d\u00e2y th\u1ef1c hi\u1ec7n nhi\u1ec7m v\u1ee5 th\u1ef1c t\u1ebf theo th\u1eddi gian. 14 AWG c\u00f3 \u0111i\u1ec7n tr\u1edf 3,07 ohm\/1.000 feet, cao h\u01a1n g\u1ea7n 381% so v\u1edbi 12 AWG. C\u00e1c \u0111o\u1ea1n d\u00e2y d\u00e0i 14 AWG cho th\u1ea5y s\u1ef1 s\u1ee5t \u00e1p nhanh h\u01a1n d\u1ef1 ki\u1ebfn \u2013 ngay c\u1ea3 khi d\u00f2ng \u0111i\u1ec7n n\u1eb1m trong gi\u1edbi h\u1ea1n ampacity.<\/p>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4582\" src=\"https:\/\/huyuglobal.com\/wp-content\/uploads\/2026\/10\/What-14-AWG-Actually-Is-and-The-Ampacity-Table.webp\" alt=\"14 AWG th\u1ef1c s\u1ef1 l\u00e0 g\u00ec v\u00e0 b\u1ea3ng ampacity\" width=\"1448\" height=\"1086\" \/><\/p>\n<h2>B\u1ea3ng Ampacity, v\u00e0 T\u1ea1i Sao C\u00f3 Ba C\u1ed9t<\/h2>\n<p>D\u1eef li\u1ec7u \u0111\u01b0\u1ee3c l\u1ea5y t\u1eeb B\u1ea3ng NEC 310.16, tr\u00ecnh b\u00e0y c\u00e1c gi\u00e1 tr\u1ecb ampacity cho ph\u00e9p v\u1edbi nhi\u1ec7t \u0111\u1ed9 m\u00f4i tr\u01b0\u1eddng 30 \u00b0C v\u00e0 s\u1eed d\u1ee5ng t\u1ed1i \u0111a ba d\u00e2y d\u1eabn mang d\u00f2ng \u0111i\u1ec7n trong m\u1ed9t \u1ed1ng ho\u1eb7c c\u00e1p.<\/p>\n<table>\n<tbody>\n<tr>\n<th>D\u00e2y d\u1eabn<\/th>\n<th>60 \u00b0C<\/th>\n<th>75 \u00b0C<\/th>\n<th>90 \u00b0C<\/th>\n<th>Gi\u1edbi h\u1ea1n 240.4(D)<\/th>\n<\/tr>\n<tr>\n<td>D\u00e2y \u0111\u1ed3ng 14 AWG<\/td>\n<td>15 A<\/td>\n<td>20 A<\/td>\n<td>25 A<\/td>\n<td><strong>15 A<\/strong><\/td>\n<\/tr>\n<tr>\n<td>D\u00e2y \u0111\u1ed3ng 12 AWG<\/td>\n<td>20 A<\/td>\n<td>25 A<\/td>\n<td>30 A<\/td>\n<td>20 A<\/td>\n<\/tr>\n<tr>\n<td>10 AWG \u0111\u1ed3ng<\/td>\n<td>30 A<\/td>\n<td>35 A<\/td>\n<td>40 A<\/td>\n<td>30 A<\/td>\n<\/tr>\n<tr>\n<td>D\u00e2y nh\u00f4m 14 AWG<\/td>\n<td colspan=\"3\">Kh\u00f4ng li\u1ec7t k\u00ea cho s\u1eed d\u1ee5ng m\u1ea1ch nh\u00e1nh<\/td>\n<td>\u2014<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Ba c\u1ed9t \u0111\u01b0\u1ee3c t\u1ea1o ra do c\u00f3 c\u00e1c lo\u1ea1i c\u00e1ch \u0111i\u1ec7n v\u1edbi x\u1ebfp h\u1ea1ng nhi\u1ec7t \u0111\u1ed9 kh\u00e1c nhau. V\u00ed d\u1ee5, lo\u1ea1i TW v\u00e0 UF \u0111\u01b0\u1ee3c x\u1ebfp h\u1ea1ng 60 \u00b0C; c\u00e1c lo\u1ea1i THW, THWN v\u00e0 XHHW \u0111\u01b0\u1ee3c x\u1ebfp h\u1ea1ng 75 \u00b0C; v\u00e0 c\u00e1c lo\u1ea1i THHN, THWN-2 v\u00e0 XHHW-2 \u0111\u01b0\u1ee3c x\u1ebfp h\u1ea1ng 90 \u00b0C.<\/p>\n<p>Hai quy \u0111\u1ecbnh quy\u1ebft \u0111\u1ecbnh khi n\u00e0o s\u1eed d\u1ee5ng m\u1ed9t c\u1ed9t. Quy \u0111\u1ecbnh \u0111\u1ea7u ti\u00ean, NEC 110.14(C), y\u00eau c\u1ea7u k\u00edch th\u01b0\u1edbc \u0111\u1ea7u cu\u1ed1i c\u1ee7a m\u1ea1ch d\u1ef1a tr\u00ean m\u1ee9c nhi\u1ec7t \u0111\u1ed9 th\u1ea5p nh\u1ea5t \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong m\u1ea1ch. H\u1ea7u h\u1ebft c\u00e1c c\u1ea7u dao v\u00e0 \u0111\u1ea7u thi\u1ebft b\u1ecb trong d\u00e2n d\u1ee5ng \u0111\u01b0\u1ee3c \u0111\u00e1nh gi\u00e1 \u1edf 75 \u00b0C v\u00e0 c\u00e1c thi\u1ebft b\u1ecb c\u0169\/nh\u1ecf h\u01a1n ch\u1ee7 y\u1ebfu \u0111\u01b0\u1ee3c \u0111\u00e1nh gi\u00e1 \u1edf 60 \u00b0C. Quy \u0111\u1ecbnh th\u1ee9 hai quy \u0111\u1ecbnh r\u1eb1ng 90 \u00b0C ch\u1ec9 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho m\u1ee5c \u0111\u00edch gi\u1ea3m c\u00f4ng su\u1ea5t thay v\u00ec \u0111\u00e1nh gi\u00e1 th\u1ef1c t\u1ebf, t\u1ee9c l\u00e0 n\u00f3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho c\u00e1c ph\u00e9p t\u00ednh nhi\u1ec7t \u0111\u1ed9 v\u00e0 b\u00f3 d\u00e2y v\u00e0 ch\u1ec9 sau \u0111\u00f3 so s\u00e1nh v\u1edbi \u0111\u00e1nh gi\u00e1 \u0111\u1ea7u cu\u1ed1i. Do \u0111\u00f3, n\u1ebfu 25 ampe \u0111\u01b0\u1ee3c l\u1ea5y t\u1eeb c\u1ed9t 90 \u00b0C v\u00e0 m\u1ed9t c\u1ea7u dao \u0111\u01b0\u1ee3c k\u00edch th\u01b0\u1edbc t\u01b0\u01a1ng \u1ee9ng th\u00ec n\u00f3 vi ph\u1ea1m c\u1ea3 hai quy \u0111\u1ecbnh v\u00e0 y\u00eau c\u1ea7u an to\u00e0n ch\u00e1y n\u1ed5.<\/p>\n<h2>4(D): T\u1ea1i sao 14 AWG lu\u00f4n l\u00e0 15 Ampe<\/h2>\n<p>NEC 240.4(D) l\u00e0m r\u00f5 v\u1ea5n \u0111\u1ec1 \u0111ang \u0111\u01b0\u1ee3c \u0111\u1ec1 c\u1eadp. Ti\u00eau chu\u1ea9n d\u00e2y d\u1eabn nh\u1ecf l\u00e0 m\u1ed9t gi\u1edbi h\u1ea1n \u0111\u1eb7t ra gi\u1edbi h\u1ea1n cho c\u00e1c thi\u1ebft b\u1ecb gi\u1edbi h\u1ea1n d\u00f2ng \u0111i\u1ec7n cho c\u00e1c k\u00edch th\u01b0\u1edbc d\u00e2y nh\u1ecf nh\u1ea5t:<\/p>\n<ul>\n<li>14 AWG \u0111\u1ed3ng \u2192 t\u1ed1i \u0111a 15 A<\/li>\n<li>12 AWG \u0111\u1ed3ng \u2192 t\u1ed1i \u0111a 20 A<\/li>\n<li>10 AWG \u0111\u1ed3ng \u2192 t\u1ed1i \u0111a 30 A<\/li>\n<\/ul>\n<p>Gi\u1edbi h\u1ea1n n\u00e0y \u00e1p d\u1ee5ng b\u1ea5t k\u1ec3 lo\u1ea1i c\u00e1ch \u0111i\u1ec7n \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng, ho\u1eb7c n\u1ebfu c\u00e1c k\u1ebft n\u1ed1i \u0111\u1ea7u cu\u1ed1i \u0111\u01b0\u1ee3c \u0111\u00e1nh gi\u00e1 v\u01b0\u1ee3t qu\u00e1 ampe t\u1ed1i \u0111a cho d\u00e2y nh\u1ecf h\u01a1n. V\u00ed d\u1ee5, b\u1ea1n c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng d\u00e2y 14 AWG THHN v\u1edbi \u0111\u00e1nh gi\u00e1 25 A v\u00e0 k\u1ebft n\u1ed1i n\u00f3 v\u1edbi c\u1ea7u dao 75\u00b0C, nh\u01b0ng c\u1ea7u dao v\u1eabn b\u1ecb gi\u1edbi h\u1ea1n \u1edf 15 A. Nguy\u00ean t\u1eafc \u0111\u1eb1ng sau quy t\u1eafc n\u00e0y l\u00e0 c\u00e1c k\u00edch th\u01b0\u1edbc d\u00e2y nh\u1ecf th\u01b0\u1eddng k\u1ebft th\u00fac t\u1ea1i c\u00e1c \u0111\u1ea7u c\u1ea7u dao m\u00e0 kh\u00f4ng c\u00f3 \u0111\u1ee7 kh\u1ea3 n\u0103ng ch\u1ecbu nhi\u1ec7t.<\/p>\n<p>\u0110i\u1ec3m n\u00e0y \u0111\u00e1nh d\u1ea5u s\u1ef1 kh\u00e1c bi\u1ec7t ch\u00ednh gi\u1eefa hai lo\u1ea1i d\u00e2y d\u1eabn \u1edf \u0111\u00e2y \u2013 14 AWG kh\u00f4ng c\u00f3 m\u1ee9c \u0111\u1ed9 linh ho\u1ea1t nh\u01b0 c\u00e1c k\u00edch th\u01b0\u1edbc d\u00e2y l\u1edbn h\u01a1n v\u1ec1 ampacity v\u00e0 vi\u1ec7c s\u1eed d\u1ee5ng c\u1ea7u dao.<\/p>\n<p>Do \u0111\u00f3, 14 AWG kh\u00f4ng th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong m\u1ea1ch 20 A ngay c\u1ea3 khi \u0111o\u1ea1n d\u00e2y ng\u1eafn v\u00e0 c\u00e1c \u0111\u1ea7u n\u1ed1i t\u1ed1t. Th\u1ef1c t\u1ebf l\u00e0 12 AWG m\u1edbi c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng. N\u1ebfu b\u1ea1n \u0111ang l\u00e0m vi\u1ec7c v\u1edbi logic k\u00edch th\u01b0\u1edbc l\u1ea7n \u0111\u1ea7u ti\u00ean, ph\u01b0\u01a1ng ph\u00e1p c\u01a1 b\u1ea3n \u2014 t\u00ednh to\u00e1n t\u1ea3i, sau \u0111\u00f3 d\u00e2y d\u1eabn, r\u1ed3i b\u1ea3o v\u1ec7 \u2014 \u0111\u01b0\u1ee3c tr\u00ecnh b\u00e0y trong gi\u1ea3i th\u00edch n\u00e0y v\u1ec1 <a href=\"https:\/\/huyuglobal.com\/vi\/blog\/minimum-circuit-ampacity\/\">c\u00e1ch x\u00e1c \u0111\u1ecbnh ampacity m\u1ea1ch t\u1ed1i thi\u1ec3u<\/a>.<\/p>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4583\" src=\"https:\/\/huyuglobal.com\/wp-content\/uploads\/2026\/10\/Why-14-AWG-Is-Always-15-Amps.webp\" alt=\"T\u1ea1i sao 14 AWG lu\u00f4n l\u00e0 15 Ampe\" width=\"1448\" height=\"1086\" \/><\/p>\n<h2>B\u1eaby NM-B<\/h2>\n<p>Trong l\u1eafp \u0111\u1eb7t \u0111i\u1ec7n gia \u0111\u00ecnh, h\u1ea7u h\u1ebft c\u00e1c d\u00e2y 14 AWG \u0111\u1ebfn t\u1eeb c\u00e1p NM-B, c\u00f2n \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 Romex. D\u00e2y NM-B c\u00f3 \u0111\u00e1nh gi\u00e1 60 \u00b0C, v\u00e0 v\u00ec v\u1eady, theo NEC 334.80, ampacity ch\u1ec9 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u0111o trong c\u1ed9t 60 \u00b0C m\u1eb7c d\u00f9 d\u00e2y THHN c\u00f3 th\u1ec3 ch\u1ea1y \u1edf 90 \u00b0C.<\/p>\n<p>\u0110i\u1ec1u n\u00e0y c\u00f3 ngh\u0129a l\u00e0 c\u00f3 hai gi\u1edbi h\u1ea1n \u0111\u1ed1i ngh\u1ecbch \u0111ang t\u1ed3n t\u1ea1i. Trong h\u00e0ng 60 \u00b0C, ampacity \u0111\u01b0\u1ee3c \u0111\u00e1nh gi\u00e1 \u1edf 15 ampe, v\u00e0 theo 240.4(D), c\u0169ng l\u00e0 15 ampe. Do \u0111\u00f3, khi s\u1eed d\u1ee5ng d\u00e2y 14 AWG v\u1edbi c\u1ea7u dao 15 ampe, vi\u1ec7c l\u00e0m quen v\u1edbi s\u1ef1 k\u1ebft h\u1ee3p n\u00e0y s\u1ebd kh\u00f4ng g\u00e2y kh\u00f3 kh\u0103n cho b\u1ea1n trong vi\u1ec7c \u0111i d\u00e2y nh\u00e0. H\u01a1n n\u1eefa, trong tr\u01b0\u1eddng h\u1ee3p b\u1ea1n t\u00ecm th\u1ea5y c\u00f9ng lo\u1ea1i d\u00e2y (14 AWG THHN) trong m\u1ed9t d\u1ef1 \u00e1n l\u1eafp \u0111\u1eb7t kh\u00e1c (ch\u1eb3ng h\u1ea1n nh\u01b0 h\u1ec7 th\u1ed1ng \u1ed1ng d\u1eabn), ampacity v\u1eabn gi\u1eef \u1edf m\u1ee9c 15 ampe, v\u00ec c\u00f9ng quy \u0111\u1ecbnh 240.4(D) s\u1ebd \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng.<\/p>\n<p>H\u1ea7u h\u1ebft c\u00e1c l\u1eafp \u0111\u1eb7t \u0111i\u1ec7n th\u1ea5t b\u1ea1i khi n\u00f3i \u0111\u1ebfn c\u00e1c quy t\u1eafc gi\u1ea3m c\u00f4ng su\u1ea5t. V\u00ec d\u00e2y NM-B kh\u00f4ng th\u1ec3 \u0111\u1eb7t trong c\u1ed9t nhi\u1ec7t \u0111\u1ed9 cao h\u01a1n, \u0111i\u1ec1u n\u00e0y g\u1ea7n nh\u01b0 l\u00e0m cho vi\u1ec7c t\u00ednh \u0111\u1ebfn hi\u1ec7u ch\u1ec9nh nhi\u1ec7t \u0111\u1ed9 m\u00f4i tr\u01b0\u1eddng v\u00e0 \u0111i\u1ec1u ch\u1ec9nh b\u00f3 d\u00e2y tr\u1edf n\u00ean kh\u00f4ng th\u1ec3. Khi d\u00e2y NM-B \u0111\u01b0\u1ee3c \u0111\u1eb7t trong g\u00e1c m\u00e1i n\u00f3ng, c\u00f4ng su\u1ea5t c\u1ee7a n\u00f3 gi\u1ea3m, v\u00e0 b\u1ed9 ng\u1eaft m\u1ea1ch kh\u00f4ng th\u1ec3 b\u00f9 \u0111\u1eafp cho s\u1ef1 m\u1ea5t c\u00f4ng su\u1ea5t n\u00e0y. C\u00e1ch nhi\u1ec7t \u0111\u1ed9 m\u00f4i tr\u01b0\u1eddng v\u00e0 s\u1ed1 l\u01b0\u1ee3ng d\u00e2y d\u1eabn t\u01b0\u01a1ng t\u00e1c v\u1edbi b\u1ea3ng c\u01a1 s\u1edf \u0111\u01b0\u1ee3c \u0111\u1ec1 c\u1eadp trong b\u00e0i vi\u1ebft n\u00e0y v\u1ec1 <a href=\"https:\/\/huyuglobal.com\/vi\/blog\/nec-requirements-for-wires-and-the-voltage-they-carry\/\">Y\u00eau c\u1ea7u NEC \u0111\u1ed1i v\u1edbi lo\u1ea1i d\u00e2y v\u00e0 \u0111i\u1ec7n \u00e1p m\u00e0 ch\u00fang mang<\/a>.<\/p>\n<h2>\u0110\u1ed3ng so v\u1edbi Nh\u00f4m \u1edf k\u00edch th\u01b0\u1edbc n\u00e0y<\/h2>\n<p>Vi\u1ec7c kh\u00f4ng c\u00f3 th\u1ecb tr\u01b0\u1eddng nh\u00f4m 14 AWG kh\u1ea3 thi l\u00e0 m\u1ed9t th\u1ef1c t\u1ebf \u0111\u00e3 bi\u1ebft. Th\u1ef1c t\u1ebf, trong thi\u1ebft k\u1ebf d\u00e2y d\u1eabn m\u1ea1ch nh\u00e1nh v\u00e0 d\u00e2y d\u1eabn c\u1ea5p ngu\u1ed3n, nh\u00f4m kh\u00f4ng n\u1eb1m trong danh s\u00e1ch ng\u1eafn c\u00e1c c\u1ee1 d\u00e2y nh\u1ecf. L\u00fd do l\u00e0 nh\u00f4m g\u1eb7p v\u1ea5n \u0111\u1ec1 l\u1edbn v\u1edbi c\u00e1c k\u1ebft n\u1ed1i xu\u1ea5t hi\u1ec7n mu\u1ed9n v\u00e0o cu\u1ed1i nh\u1eefng n\u0103m 1960 v\u00e0 1970 ch\u00ednh x\u00e1c do c\u00e1c v\u1ea5n \u0111\u1ec1 k\u1ebft n\u1ed1i v\u1edbi d\u00e2y c\u1ee1 nh\u1ecf.<\/p>\n<p>Nh\u00f4m tr\u1edf n\u00ean kh\u1ea3 thi b\u1eaft \u0111\u1ea7u t\u1eeb k\u00edch th\u01b0\u1edbc 8 AWG khi vi\u1ec7c ti\u1ebft ki\u1ec7m tr\u1ecdng l\u01b0\u1ee3ng v\u00e0 v\u1eadt li\u1ec7u bi\u1ec7n minh cho vi\u1ec7c s\u1eed d\u1ee5ng d\u00e2y l\u1edbn h\u01a1n. L\u01b0u \u00fd r\u1eb1ng d\u00e2y nh\u00f4m mang d\u00f2ng \u0111i\u1ec7n th\u1ea5p h\u01a1n \u0111\u1ebfn 20% so v\u1edbi d\u00e2y \u0111\u1ed3ng do \u0111i\u1ec7n tr\u1edf cao h\u01a1n, kho\u1ea3ng 65% l\u1edbn h\u01a1n so v\u1edbi \u0111\u1ed3ng.<\/p>\n<p>Do \u0111\u00f3, d\u00e2y \u0111\u1ed3ng ch\u1eafc ch\u1eafn v\u1eabn l\u00e0 l\u1ef1a ch\u1ecdn duy nh\u1ea5t cho ph\u00e2n kh\u00fac 14 AWG. So s\u00e1nh r\u1ed9ng h\u01a1n gi\u1eefa hai v\u1eadt li\u1ec7u, bao g\u1ed3m n\u01a1i m\u1ed7i lo\u1ea1i th\u1ef1c s\u1ef1 l\u00e0 l\u1ef1a ch\u1ecdn t\u1ed1t h\u01a1n, \u0111\u01b0\u1ee3c tr\u00ecnh b\u00e0y trong gi\u1ea3i th\u00edch n\u00e0y v\u1ec1 <a href=\"https:\/\/huyuglobal.com\/vi\/blog\/for-electric-power-transmission-copper-or-aluminium-wire-is-used\/\">l\u00fd do t\u1ea1i sao c\u1ea3 \u0111\u1ed3ng v\u00e0 nh\u00f4m \u0111\u1ec1u \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho d\u00e2y d\u1eabn \u0111i\u1ec7n<\/a>.<\/p>\n<h2>Gi\u1ea3m c\u00f4ng su\u1ea5t: Khi 14 AWG kh\u00f4ng c\u00f2n \u0111\u1ee7<\/h2>\n<p>B\u1ea3ng gi\u1ea3 \u0111\u1ecbnh kh\u00f4ng c\u00f3 qu\u00e1 ba d\u00e2y truy\u1ec1n d\u00f2ng \u0111i\u1ec7n \u1edf nhi\u1ec7t \u0111\u1ed9 m\u00f4i tr\u01b0\u1eddng 30 \u00b0C. Nh\u1eefng gi\u1ea3 \u0111\u1ecbnh n\u00e0y th\u01b0\u1eddng kh\u00f4ng \u0111\u00fang, v\u00e0 ngay c\u1ea3 v\u1edbi d\u00e2y 14 AWG, s\u1ebd s\u1edbm c\u00f3 s\u1ef1 gi\u1ea3m c\u00f4ng su\u1ea5t r\u00f5 r\u1ec7t c\u1ee7a d\u00e2y d\u1eabn d\u01b0\u1edbi ng\u01b0\u1ee1ng 15 A, d\u1eabn \u0111\u1ebfn vi\u1ec7c n\u00f3 tr\u1edf n\u00ean kh\u00f4ng tu\u00e2n th\u1ee7 thay v\u00ec ch\u1ec9 \u1edf m\u1ee9c gi\u1edbi h\u1ea1n tu\u00e2n th\u1ee7.<\/p>\n<table>\n<tbody>\n<tr>\n<th>T\u00ecnh tr\u1ea1ng<\/th>\n<th>Y\u1ebfu t\u1ed1<\/th>\n<th>\u00c1p d\u1ee5ng cho c\u01a1 s\u1edf 90 \u00b0C (25 A)<\/th>\n<\/tr>\n<tr>\n<td>4\u20136 d\u00e2y d\u1eabn mang d\u00f2ng \u0111i\u1ec7n<\/td>\n<td>80%<\/td>\n<td>20 A<\/td>\n<\/tr>\n<tr>\n<td>7\u20139 d\u00e2y d\u1eabn mang d\u00f2ng \u0111i\u1ec7n<\/td>\n<td>70%<\/td>\n<td>5 A<\/td>\n<\/tr>\n<tr>\n<td>10\u201320 d\u00e2y d\u1eabn mang d\u00f2ng \u0111i\u1ec7n<\/td>\n<td>50%<\/td>\n<td>12,5 A<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>H\u00e3y xem x\u00e9t m\u1ed9t v\u00ed d\u1ee5 r\u00f5 r\u00e0ng: b\u1ed1n d\u00e2y g\u1ed3m 14 AWG trong m\u00f4i tr\u01b0\u1eddng chung c\u1ee7a m\u1ed9t \u1ed1ng d\u1eabn. \u0110\u1ecbnh m\u1ee9c ampe 25A nh\u00e2n v\u1edbi 0,80 cho ra 20A. \u0110i\u1ec1u \u0111\u00f3 v\u1eabn \u0111\u1ee7 v\u00ec m\u1ee9c t\u1ed1i thi\u1ec3u c\u1ea7n l\u00e0 15A, \u0111\u1ee7 cho m\u1ed9t b\u1ed9 ng\u1eaft 15A. Khi s\u1ed1 l\u01b0\u1ee3ng d\u00e2y l\u00ean \u0111\u1ebfn b\u1ea3y, \u0111\u1ecbnh m\u1ee9c ampe gi\u1ea3m xu\u1ed1ng c\u00f2n 17,5A, v\u1eabn l\u1edbn h\u01a1n 15A nh\u01b0ng m\u1ee9c dung sai kh\u00f4ng \u0111\u1ea1t y\u00eau c\u1ea7u. N\u1ebfu kh\u00f4ng gian qu\u00e1 n\u00f3ng, ngh\u0129a l\u00e0 kh\u1ea3 n\u0103ng ch\u1ecbu d\u00f2ng gi\u1ea3m xu\u1ed1ng d\u01b0\u1edbi m\u1ee9c t\u1ed1i thi\u1ec3u y\u00eau c\u1ea7u. Trong tr\u01b0\u1eddng h\u1ee3p \u0111\u00f3, ph\u1ea3i chuy\u1ec3n sang d\u00e2y d\u00e0y h\u01a1n nh\u01b0 12 AWG.<\/p>\n<p>\u0110\u01a1n gi\u1ea3n c\u1ee7a tr\u01b0\u1eddng h\u1ee3p d\u00e2y 14 AWG l\u00e0, ngay khi v\u01b0\u1ee3t qu\u00e1 s\u1ed1 l\u01b0\u1ee3ng d\u00e2y ho\u1eb7c nhi\u1ec7t \u0111\u1ed9, t\u1ed1t h\u01a1n n\u00ean chuy\u1ec3n sang d\u00e2y lo\u1ea1i t\u1ed1t h\u01a1n l\u00e0 12 AWG.<\/p>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4584\" src=\"https:\/\/huyuglobal.com\/wp-content\/uploads\/2026\/10\/When-14-AWG-Stops-Being-Enough.webp\" alt=\"Khi n\u00e0o 14 AWG kh\u00f4ng c\u00f2n \u0111\u1ee7\" width=\"1448\" height=\"1086\" \/><\/p>\n<h2>S\u1ee5t \u00e1p v\u00e0 chi\u1ec1u d\u00e0i d\u00e2y<\/h2>\n<p>Dung l\u01b0\u1ee3ng d\u00f2ng \u0111i\u1ec7n ch\u1ec9 l\u00e0 m\u1ed9t m\u1eb7t c\u1ee7a v\u1ea5n \u0111\u1ec1; \u1edf ph\u00eda xa, ph\u1ea3i \u0111\u1eb7t c\u00e2u h\u1ecfi kh\u00e1c: T\u00f4i c\u00f3 \u0111\u1ee7 \u0111i\u1ec7n \u00e1p kh\u00f4ng?<\/p>\n<p>Trong tr\u01b0\u1eddng h\u1ee3p m\u1ea1ch 15-A 240-V, d\u00e2y \u0111\u1ed3ng c\u1ee1 14 AWG cho th\u1ea5y s\u1ee5t \u00e1p kho\u1ea3ng 1,91% \u1edf kho\u1ea3ng c\u00e1ch 50 feet v\u00e0 3,81% \u1edf tr\u00ean 100 feet. S\u1eed d\u1ee5ng m\u1ea1ch 120-V c\u00f3 ngh\u0129a l\u00e0 s\u1ee5t \u00e1p t\u01b0\u01a1ng t\u1ef1 s\u1ebd t\u0103ng g\u1ea5p \u0111\u00f4i t\u1ef7 l\u1ec7 ph\u1ea7n tr\u0103m.<\/p>\n<p>Do \u0111\u00f3, 14 AWG c\u00f3 th\u1ec3 qu\u00e1 l\u1edbn \u2014 c\u00f3 th\u1ec3 qu\u00e1 l\u1edbn \u2014 cho b\u1ea5t k\u1ef3 d\u00e2y d\u1eabn n\u00e0o tr\u00ean c\u00e1c \u0111o\u1ea1n d\u00e0i. Theo h\u01b0\u1edbng d\u1eabn c\u1ee7a NEC, s\u1ee5t \u00e1p 3% tr\u00ean m\u1ea1ch nh\u00e1nh v\u00e0 5% t\u1eeb ngu\u1ed3n \u0111\u1ebfn t\u1ea3i l\u00e0 cho ph\u00e9p. \u1ede \u0111o\u1ea1n d\u00e0i 50 feet, b\u1ea1n \u0111\u1ea1t s\u1ee5t \u00e1p 3% tr\u00ean m\u1ea1ch nh\u00e1nh v\u1edbi d\u00e2y 14 AWG cho m\u1ea1ch 120V, \u0111i\u1ec1u n\u00e0y kh\u00f4ng qu\u00e1 t\u1ec7 cho \u0111\u1ebfn khi b\u1ea1n \u0111o chi\u1ec1u d\u00e0i c\u00e1p thay v\u00ec kho\u1ea3ng c\u00e1ch tr\u1ef1c ti\u1ebfp.<\/p>\n<p>C\u00e1c \u0111o\u1ea1n d\u00e0i c\u0169ng g\u00e2y ra nhi\u1ec1u tri\u1ec7u ch\u1ee9ng suy gi\u1ea3m b\u00ed \u1ea9n \u2014 \u0111\u00e8n m\u1edd \u1edf cu\u1ed1i m\u1ea1ch, \u0111\u1ed9ng c\u01a1 k\u00eau \u00f9 thay v\u00ec kh\u1edfi \u0111\u1ed9ng, thi\u1ebft b\u1ecb t\u1ef1 reset khi thi\u1ebft b\u1ecb kh\u00e1c b\u1eadt. C\u1ea3 ba \u0111\u1ec1u l\u00e0 tri\u1ec7u ch\u1ee9ng s\u1ee5t \u00e1p trong h\u00ecnh th\u1ee9c kh\u00e1c. N\u1ebfu \u0111o\u1ea1n d\u00e2y d\u00e0i, h\u00e3y s\u1eed d\u1ee5ng d\u00e2y d\u1eabn l\u1edbn h\u01a1n thay v\u00ec ch\u1ecbu \u0111\u1ef1ng s\u1ee5t \u00e1p.<\/p>\n<h2>14 AWG \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho g\u00ec, v\u00e0 kh\u00f4ng d\u00f9ng cho g\u00ec<\/h2>\n<table>\n<tbody>\n<tr>\n<th>Ph\u00f9 h\u1ee3p<\/th>\n<th>Kh\u00f4ng ph\u00f9 h\u1ee3p<\/th>\n<\/tr>\n<tr>\n<td>M\u1ea1ch chi\u1ebfu s\u00e1ng 15 A<\/td>\n<td>M\u1ea1ch \u1ed5 c\u1eafm 20 A (c\u1ea7n 12 AWG)<\/td>\n<\/tr>\n<tr>\n<td>M\u1ea1ch \u1ed5 c\u1eafm \u0111a n\u0103ng tr\u00ean b\u1ed9 ng\u1eaft 15 A<\/td>\n<td>M\u1ea1ch thi\u1ebft b\u1ecb nh\u1ecf nh\u00e0 b\u1ebfp, ph\u1ea3i l\u00e0 20 A<\/td>\n<\/tr>\n<tr>\n<td>D\u00e2y c\u00f4ng t\u1eafc v\u00e0 d\u00e2y d\u1eabn h\u00e0nh tr\u00ecnh<\/td>\n<td>M\u1ea1ch \u1ed5 c\u1eafm ph\u00f2ng t\u1eafm, ph\u1ea3i l\u00e0 20 A<\/td>\n<\/tr>\n<tr>\n<td>M\u1ea1ch b\u00e1o kh\u00f3i v\u00e0 CO<\/td>\n<td>M\u1ea1ch \u1ed5 c\u1eafm gi\u1eb7t l\u00e0<\/td>\n<\/tr>\n<tr>\n<td>\u0110o\u1ea1n ng\u1eafn \u0111\u1ebfn \u0111\u00e8n c\u1ed1 \u0111\u1ecbnh<\/td>\n<td>M\u00e1y n\u01b0\u1edbc n\u00f3ng, m\u00e1y s\u1ea5y, b\u1ebfp, b\u1ed9 s\u1ea1c EV, \u0111i\u1ec1u h\u00f2a kh\u00f4ng kh\u00ed<\/td>\n<\/tr>\n<tr>\n<td>M\u1ea1ch thi\u1ebft b\u1ecb ti\u00eau th\u1ee5 th\u1ea5p<\/td>\n<td>B\u1ea5t k\u1ef3 m\u1ea1ch n\u00e0o v\u01b0\u1ee3t qu\u00e1 240.4(D)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Theo c\u00e1ch n\u00e0y, trong khi 14 AWG \u0111\u01b0\u1ee3c ph\u00e2n b\u1ed5 cho chi\u1ebfu s\u00e1ng chung v\u00e0 \u1ed5 c\u1eafm chung, b\u1ea5t k\u1ef3 \u1ee9ng d\u1ee5ng n\u00e0o y\u00eau c\u1ea7u t\u1ea3i c\u1ed1 \u0111\u1ecbnh kh\u00e1 cao \u0111\u1ec1u \u0111\u01b0\u1ee3c h\u1ed7 tr\u1ee3 b\u1edfi m\u1ea1ch ri\u00eang l\u1edbn h\u01a1n. Th\u1ef1c t\u1ebf, s\u1ef1 ph\u00e2n b\u1ed5 n\u00e0y l\u00e0 c\u00f3 ch\u1ee7 \u00fd, v\u00ec c\u00e1c m\u1ea1ch m\u1ee5c \u0111\u00edch chung kh\u00f4ng th\u1ec3 d\u1ef1 \u0111o\u00e1n ch\u00ednh x\u00e1c n\u00ean \u0111\u01b0\u1ee3c gi\u1eef nh\u1ecf v\u00e0 nhi\u1ec1u.<\/p>\n<p>C\u00f4ng th\u1ee9c t\u00ednh t\u1ea3i trong m\u1ea1ch 15 A \u0111\u00e1ng \u0111\u1ec3 ghi nh\u1edb. \u0110\u01a1n v\u1ecb 15 A \u1edf 120 V t\u01b0\u01a1ng \u0111\u01b0\u01a1ng 1800 W; v\u00ec h\u1ea7u h\u1ebft c\u00e1c c\u00e1ch hi\u1ec3u v\u1ec1 quy chu\u1ea9n gi\u1edbi h\u1ea1n t\u1ea3i li\u00ean t\u1ee5c \u1edf 80% (80%), n\u00ean kh\u1ea3 n\u0103ng s\u1eed d\u1ee5ng li\u00ean t\u1ee5c l\u00e0 12 A ho\u1eb7c 1440 W. Tuy nhi\u00ean, m\u00e1y s\u01b0\u1edfi 1500 W n\u1eb1m ngay ng\u01b0\u1ee1ng v\u00e0 kh\u00f4ng cho ph\u00e9p k\u1ebft n\u1ed1i th\u00eam thi\u1ebft b\u1ecb kh\u00e1c. Ph\u1ea7n t\u00ednh c\u00f4ng su\u1ea5t watt \u0111\u01b0\u1ee3c tr\u00ecnh b\u00e0y trong h\u01b0\u1edbng d\u1eabn n\u00e0y \u0111\u1ec3 <a href=\"https:\/\/huyuglobal.com\/vi\/blog\/how-many-watts-on-a-15-amp-circuit\/\">bi\u1ebft m\u1ea1ch 15 amp c\u00f3 th\u1ec3 cung c\u1ea5p bao nhi\u00eau watt<\/a>.<\/p>\n<h2>14 so v\u1edbi 12: C\u00e1ch l\u1ef1a ch\u1ecdn<\/h2>\n<p>\u0110i\u1ec1u n\u00e0y l\u00e0 do hai k\u00edch th\u01b0\u1edbc n\u00e0y t\u01b0\u01a1ng t\u1ef1 nhau v\u1ec1 gi\u00e1 c\u1ea3 v\u00e0 hi\u1ec7u su\u1ea5t n\u00ean l\u1ef1a ch\u1ecdn th\u01b0\u1eddng d\u1ef1a v\u00e0o \u201clo\u1ea1i m\u1ea1ch,\u201d thay v\u00ec \u201ct\u00ednh to\u00e1n.\u201d<\/p>\n<ul>\n<li>S\u1eed d\u1ee5ng d\u00e2y 14AWG cho m\u1ea1ch chi\u1ebfu s\u00e1ng 15 A v\u00e0 m\u1ea1ch \u1ed5 c\u1eafm \u0111a n\u0103ng, v\u00ec c\u1ea3 quy chu\u1ea9n v\u00e0 kh\u1ea3 n\u0103ng ch\u1ecbu d\u00f2ng \u0111\u1ec1u ph\u00f9 h\u1ee3p, nh\u01b0ng chi\u1ec1u d\u00e0i \u0111\u01b0\u1eddng d\u00e2y \u1edf m\u1ee9c trung b\u00ecnh.<\/li>\n<li>S\u1eed d\u1ee5ng d\u00e2y 12 AWG khi \u0111i d\u00e2y cho c\u00e1c m\u1ea1ch lo\u1ea1i 20 A: b\u1ebfp, ph\u00f2ng t\u1eafm, ph\u00f2ng gi\u1eb7t, gara, \u1ed5 c\u1eafm ngo\u00e0i tr\u1eddi, ho\u1eb7c khi \u0111\u01b0\u1eddng d\u00e2y d\u00e0i v\u00e0 s\u1ee5t \u00e1p l\u00e0 y\u1ebfu t\u1ed1 quan tr\u1ecdng.<\/li>\n<li>S\u1eed d\u1ee5ng d\u00e2y 12 AWG khi t\u00ecnh hu\u1ed1ng l\u1eafp \u0111\u1eb7t y\u00eau c\u1ea7u gi\u1ea3m d\u00f2ng \u0111\u1ecbnh m\u1ee9c d\u00e2y: g\u00e1c m\u00e1i n\u00f3ng, nhi\u1ec1u d\u00e2y trong \u1ed1ng d\u1eabn, ho\u1eb7c c\u00e1p b\u00f3 l\u1ea1i v\u1edbi nhau.<\/li>\n<li>S\u1eed d\u1ee5ng d\u00e2y 12 AWG n\u1ebfu c\u00f3 kh\u1ea3 n\u0103ng c\u1ea7n m\u1ea1ch 20 A trong t\u01b0\u01a1ng lai, v\u00ec ch\u00eanh l\u1ec7ch gi\u00e1 r\u1ea5t nh\u1ecf, trong khi chi ph\u00ed c\u1ea3i t\u1ea1o sau n\u00e0y s\u1ebd l\u1edbn.<\/li>\n<\/ul>\n<p>L\u01b0u \u00fd cu\u1ed1i v\u1ec1 x\u1eed l\u00fd: D\u00e2y 12 AWG c\u1ee9ng h\u01a1n v\u00e0 kh\u00f3 \u0111\u1eb7t trong h\u1ed9p, do \u0111\u00f3 s\u1ed1 l\u01b0\u1ee3ng d\u00e2y c\u00f3 th\u1ec3 \u0111\u1eb7t trong h\u1ed9p s\u1ebd nhi\u1ec1u h\u01a1n v\u1edbi d\u00e2y n\u00e0y. N\u1ebfu t\u0103ng k\u00edch th\u01b0\u1edbc d\u00e2y, c\u0169ng c\u1ea7n ki\u1ec3m tra th\u1ec3 t\u00edch h\u1ed9p v\u00e0 c\u1ea7u dao. So s\u00e1nh tr\u1ef1c ti\u1ebfp hai k\u00edch th\u01b0\u1edbc, bao g\u1ed3m n\u01a1i 12 AWG tr\u1edf th\u00e0nh b\u1eaft bu\u1ed9c, \u0111\u01b0\u1ee3c tr\u00ecnh b\u00e0y trong h\u01b0\u1edbng d\u1eabn n\u00e0y v\u1ec1 <a href=\"https:\/\/huyuglobal.com\/vi\/blog\/12-gauge-wire\/\">d\u00e2y 12 gauge v\u00e0 kh\u1ea3 n\u0103ng ch\u1ecbu t\u1ea3i c\u1ee7a n\u00f3<\/a>.<\/p>\n<h2>C\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p<\/h2>\n<h3>T\u00f4i c\u00f3 th\u1ec3 d\u00f9ng 20 amp tr\u00ean d\u00e2y 14 gauge kh\u00f4ng?<\/h3>\n<p>Theo NEC 240.4(D), d\u00f9 b\u1ea3ng cho th\u1ea5y 20 A v\u00e0 25 A cho d\u00e2y \u0111\u1ed3ng 14 AWG \u1edf 75\u00b0C v\u00e0 90\u00b0C t\u01b0\u01a1ng \u1ee9ng, \u0111i\u1ec1u n\u00e0y kh\u00f4ng c\u00f3 ngh\u0129a d\u00e2y \u0111\u1ed3ng 14 AWG c\u00f3 th\u1ec3 ch\u1ecbu qu\u00e1 15 A. Gi\u1edbi h\u1ea1n n\u00e0y \u00e1p d\u1ee5ng b\u1ea5t k\u1ec3 x\u1ebfp h\u1ea1ng nhi\u1ec7t hay x\u1ebfp h\u1ea1ng \u0111\u1ea7u n\u1ed1i. \u0110\u1ec3 s\u1eed d\u1ee5ng m\u1ea1ch 20 A, ph\u1ea3i d\u00f9ng d\u00e2y \u0111\u1ed3ng 12 AWG, c\u0169ng b\u1ecb gi\u1edbi h\u1ea1n 20 A theo quy \u0111\u1ecbnh NEC.<\/p>\n<h3>D\u00e2y 14 gauge c\u00f3 ch\u1ecbu \u0111\u01b0\u1ee3c 1500 watt kh\u00f4ng?<\/h3>\n<p>\u1ede 120 volt, 1500 watt s\u1eed d\u1ee5ng 12,5 amp \u2013 d\u01b0\u1edbi \u0111\u1ecbnh m\u1ee9c 15 amp v\u00e0 tr\u00ean quy t\u1eafc t\u1ea3i li\u00ean t\u1ee5c kho\u1ea3ng 12 amp. Do \u0111\u00f3, m\u1eb7c d\u00f9 c\u00f3 th\u1ec3 ch\u1ea1y trong \u0111i\u1ec1u ki\u1ec7n n\u00e0y, m\u1ea1ch s\u1ebd ch\u1ea1y li\u00ean t\u1ee5c \u1edf 1500 watt v\u00e0 d\u00e2y d\u1eabn s\u1ebd n\u00f3ng v\u00ec kh\u00f4ng c\u00f3 bi\u00ean \u0111\u1ed9 an to\u00e0n. Ng\u01b0\u1ee3c l\u1ea1i, \u1edf 240 volt, t\u1ea3i n\u00e0y ch\u1ec9 k\u00e9o 6,25 amp, n\u1eb1m trong gi\u1edbi h\u1ea1n an to\u00e0n.<\/p>\n<h3>D\u00e2y 14 gauge c\u00f3 ch\u1ecbu \u0111\u01b0\u1ee3c 30 amp kh\u00f4ng?<\/h3>\n<p>Ho\u00e0n to\u00e0n kh\u00f4ng. \u0110\u1ecbnh m\u1ee9c t\u1ed1i \u0111a c\u1ee7a d\u00e2y \u0111\u1ed3ng 14 AWG trong B\u1ea3ng 310.16 l\u00e0 25 A \u1edf nhi\u1ec7t \u0111\u1ed9 m\u00f4i tr\u01b0\u1eddng 90\u00b0C, n\u00ean kh\u00f4ng th\u1ec3 d\u00f9ng l\u00e0m \u0111i\u1ec3m k\u1ebft th\u00fac. V\u1ec1 gi\u1edbi h\u1ea1n theo 240.4(D), \u0111\u1ecbnh m\u1ee9c t\u1ed1i \u0111a l\u00e0 15 A. M\u1ea1ch 30 A ph\u1ea3i d\u00f9ng d\u00e2y \u0111\u1ed3ng 10 AWG, b\u1ecb gi\u1edbi h\u1ea1n 30 A theo c\u00f9ng quy \u0111\u1ecbnh.<\/p>\n<h3>C\u00f3 n\u00ean s\u1eed d\u1ee5ng d\u00e2y 12 hay 14 gauge cho c\u1ea7u dao 20 amp trong m\u00e3 \u0111i\u1ec7n d\u00e2n d\u1ee5ng kh\u00f4ng?<\/h3>\n<p>S\u1eed d\u1ee5ng 12 AWG. C\u1ea7u dao 20A tr\u00ean d\u00e2y 14 AWG vi ph\u1ea1m 240.4(D) v\u00e0 s\u1ebd \u0111\u1ec3 d\u00e2y kh\u00f4ng \u0111\u01b0\u1ee3c b\u1ea3o v\u1ec7 \u1edf gi\u1edbi h\u1ea1n c\u1ee7a n\u00f3. Tuy nhi\u00ean, tr\u00ean th\u1ef1c t\u1ebf, h\u1ea7u h\u1ebft c\u00e1c m\u1ea1ch 20A d\u00e2n d\u1ee5ng \u2014 thi\u1ebft b\u1ecb nh\u1ecf nh\u00e0 b\u1ebfp, ph\u00f2ng t\u1eafm, gi\u1eb7t \u1ee7i \u2014 \u0111\u1ec1u y\u00eau c\u1ea7u 20A. Do \u0111\u00f3, 12 AWG l\u00e0 ti\u00eau chu\u1ea9n cho c\u00e1c ph\u00f2ng n\u00e0y b\u1ea5t k\u1ec3 l\u1ef1a ch\u1ecdn c\u1ea7u dao. 14 AWG ch\u1ec9 n\u00ean d\u00f9ng cho m\u1ea1ch 15A.<\/p>\n<h2>T\u00e0i li\u1ec7u tham kh\u1ea3o<\/h2>\n<ol>\n<li><a href=\"https:\/\/www.nfpa.org\/codes-and-standards\/nfpa-70-standard-development\/70\" rel=\"nofollow noopener\" target=\"_blank\">NFPA \u2014 NFPA 70 National Electrical Code, B\u1ea3ng 310.16, M\u1ee5c 240.4(D), 110.14(C) v\u00e0 334.80<\/a><\/li>\n<li><a href=\"https:\/\/www.southwire.com\/\" rel=\"nofollow noopener\" target=\"_blank\">Southwire \u2014 d\u1eef li\u1ec7u \u0111i\u1ec7n tr\u1edf d\u00e2y d\u1eabn, kh\u1ea3 n\u0103ng ch\u1ecbu d\u00f2ng v\u00e0 c\u1ea5u tr\u00fac c\u00e1p NM-B<\/a><\/li>\n<li><a href=\"https:\/\/www.nema.org\/\" rel=\"nofollow noopener\" target=\"_blank\">NEMA \u2014 ti\u00eau chu\u1ea9n d\u00e2y d\u1eabn x\u00e2y d\u1ef1ng v\u00e0 \u0111\u1ecbnh ngh\u0129a l\u1edbp nhi\u1ec7t c\u00e1ch \u0111i\u1ec7n<\/a><\/li>\n<li><a href=\"https:\/\/www.grainger.com\/\" rel=\"nofollow noopener\" target=\"_blank\">Grainger \u2014 gi\u00e1 hi\u1ec7n t\u1ea1i v\u00e0 d\u1eef li\u1ec7u k\u1ef9 thu\u1eadt cho d\u00e2y d\u1eabn x\u00e2y d\u1ef1ng 14 AWG v\u00e0 12 AWG<\/a><\/li>\n<li><a href=\"https:\/\/www.iaei.org\/\" rel=\"nofollow noopener\" target=\"_blank\">International Association of Electrical Inspectors \u2014 di\u1ec5n gi\u1ea3i b\u1ea3o v\u1ec7 qu\u00e1 d\u00f2ng cho d\u00e2y d\u1eabn nh\u1ecf<\/a><\/li>\n<li><a href=\"https:\/\/www.ecmweb.com\/\" rel=\"nofollow noopener\" target=\"_blank\">EC&amp;M Magazine \u2014 c\u00e1c h\u1ec7 s\u1ed1 \u0111i\u1ec1u ch\u1ec9nh ampacity v\u00e0 h\u01b0\u1edbng d\u1eabn nhi\u1ec7t \u0111\u1ed9 \u0111\u1ea7u cu\u1ed1i<\/a><\/li>\n<li><a href=\"https:\/\/www.eaton.com\/\" rel=\"nofollow noopener\" target=\"_blank\">Eaton \u2014 x\u1ebfp h\u1ea1ng \u0111\u1ea7u cu\u1ed1i c\u1ee7a b\u1ed9 ng\u1eaft m\u1ea1ch v\u00e0 th\u00f4ng s\u1ed1 k\u1ef9 thu\u1eadt trung t\u00e2m t\u1ea3i d\u00e2n d\u1ee5ng<\/a><\/li>\n<li><a href=\"https:\/\/www.energy.gov\/\" rel=\"nofollow noopener\" target=\"_blank\">B\u1ed9 N\u0103ng l\u01b0\u1ee3ng Hoa K\u1ef3 \u2014 h\u01b0\u1edbng d\u1eabn \u0111i d\u00e2y d\u00e2n d\u1ee5ng v\u00e0 t\u1ea3i \u0111i\u1ec7n<\/a><\/li>\n<\/ol>\n<h2>K\u1ebft lu\u1eadn<\/h2>\n<p>D\u00e2y \u0111\u1ed3ng 14 AWG \u0111\u01b0\u1ee3c x\u1ebfp h\u1ea1ng 15 A \u1edf 60 \u00b0C; 20 A \u1edf 75 \u00b0C; v\u00e0 25 A \u1edf 90 \u00b0C. Tuy nhi\u00ean, theo m\u00e3, b\u1ea1n ch\u1ec9 c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng ch\u00ednh x\u00e1c m\u1ed9t trong nh\u1eefng x\u1ebfp h\u1ea1ng \u0111\u00f3 \u0111\u1ec3 b\u1ea3o v\u1ec7 qu\u00e1 d\u00f2ng: 15 A. \u0110\u00f3 l\u00e0 c\u00e1ch ph\u1ea7n 240.4(D) ho\u1ea1t \u0111\u1ed9ng, \u0111i\u1ec1u n\u00e0y l\u00e0m cho c\u1ee1 d\u00e2y n\u00e0y tr\u1edf n\u00ean d\u1ef1 \u0111o\u00e1n \u0111\u01b0\u1ee3c nh\u1ea5t v\u00e0 \u00edt linh ho\u1ea1t nh\u1ea5t khi tri\u1ec3n khai \u0111i d\u00e2y trong c\u00e1c t\u00f2a nh\u00e0 d\u00e2n d\u1ee5ng. B\u1ea1n n\u00ean s\u1eed d\u1ee5ng n\u00f3 cho c\u00e1c m\u1ea1ch 15 A trong chi\u1ebfu s\u00e1ng v\u00e0 \u1ed5 c\u1eafm \u0111a n\u0103ng, gi\u1edbi h\u1ea1n s\u1ed1 l\u01b0\u1ee3ng d\u00e2y d\u1eabn v\u00e0 nhi\u1ec7t \u0111\u1ed9 m\u00f4i tr\u01b0\u1eddng, ch\u00fa \u00fd \u0111\u1ebfn chi\u1ec1u d\u00e0i ch\u1ea1y d\u00e2y, v\u00e0 chuy\u1ec3n sang 12 AWG ngay khi b\u1ea1n c\u1ea7n tri\u1ec3n khai m\u1ed9t m\u1ea1ch \u0111\u01b0\u1ee3c x\u1ebfp h\u1ea1ng 20 A ho\u1eb7c n\u1ebfu chi\u1ec1u d\u00e0i ch\u1ea1y d\u00e2y c\u1ee7a b\u1ea1n d\u00e0i.<\/p>\n<p>&nbsp;<\/p>","protected":false},"excerpt":{"rendered":"<p>When you ask any three electricians about the ampacity of 14 gauge wire, you will hear three technically valid answers: 15, 20 or 25 amps. As far as the code table is concerned, both groups rely on the same set of data. The landmark difference is which regulation is applicable to the circuit you\u2019re dealing [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":4581,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_gspb_post_css":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-4580","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blogs"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/posts\/4580","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/comments?post=4580"}],"version-history":[{"count":2,"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/posts\/4580\/revisions"}],"predecessor-version":[{"id":4586,"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/posts\/4580\/revisions\/4586"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/media\/4581"}],"wp:attachment":[{"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/media?parent=4580"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/categories?post=4580"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/tags?post=4580"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}