Dab tsi yog nm-b cable?
NM-B cable yog ib txoj kab hluav taws xob thoob ntiaj teb uas tau teev tseg hauv National Electrical Code (NEC) ntawm Tebchaws Meskas, feem ntau siv hauv cov tsev nyob hauv kev sib txawv rau cov qhov (socket), keyboards, thiab lwm yam khoom thauj. Nws ua raws li AWG (American Wire Gauge) specifications thiab tau dhau UL (Underwriters Laboratories) ntawv pov thawj, haum rau kev lag luam cuab yeej cuab tam.
Cov qauv thiab cov khoom siv
Cov qauv ntawm NM-B cable suav nrog ib lossis ntau cov hlua ntawm cov twisted zoo 14-2/0AWG liab qab tooj liab hlau, kub-resistant 90 degree thermoplastic tub ntxhais hlau rwb thaiv tsev, raws li ASTM-B3 / B8 tus qauv . Nws sheath yog them nrog pob tshab nylon, uas yog ci rau sab nraud thiab yooj yim rau nruab los ntawm cov kav dej. Tsis tas li ntawd, lub sheath ntawm cable tuaj yeem hloov kho xim raws li cov neeg siv khoom xav tau.
Daim ntawv thov scenarios
NM-B cables yog tshwj xeeb tshaj yog haum rau lub tsev xov hlau vim lawv zoo heev thermal stability, mechanical zog, txias tsis kam, deg hardness, dabtsi yog khoov lub zog, cuam tshuam lub zog, hnav tsis kam, tshuaj tsis kam, roj kuj, roj av, thiab nws tus kheej-lubricating zog. Nws yog dav siv nyob rau hauv cov tsev nyob ua ib qho kev sib txawv rau cov qhov (socket), keyboards, thiab lwm yam loads.
Daim ntawv thov
Hom NM-B (nonmetallic-sheathed cable) yuav siv tau rau ob qho tib si nthuav tawm thiab zais ua haujlwm nyob rau hauv ib txwm qhuav qhov chaw ntawm qhov kub tsis tshaj 90 degree (nrog ampacity txwv rau qhov ntawd rau 60 degree conductors) raws li tau teev tseg hauv 2011 National Electrical Code. NM-B cable feem ntau yog siv nyob rau hauv cov kab hluav taws xob hauv tsev raws li cov khoom siv hluav taws xob rau cov qhov hluav taws xob, cov khoom siv hluav taws xob, thiab lwm yam khoom siv. NM-B cable tej zaum yuav khiav hauv huab cua voids ntawm masonry thaiv los yog pobzeb phab ntsa uas cov phab ntsa tsis ntub dej los yog qhov chaw ntub dej. Kev ntsuas hluav taws xob rau NM-B cable yog 600 volts.
Cov qauv
Hom NM-B cable ua raws li: • ASTM B-3 thiab B-8 • UL Standard 83 • UL Standard 719 • Federal Specification AA-59544 • National Electrical Code, NFPA 70. 2011 Edition • RoHS/ REACH
Specifications
Nonmetallic-Seathed Cable. 600 volt. Copper conductors. Xim-Code Jacket. Plaub tus neeg xyuas pib muaj nrog ob qhov nruab nrab.
NM-B (nonmetallic-sheathed) Cable
Hom NM-B cable yog tsim los ua 2, 3, lossis 4 tus neeg xyuas pib cable, nrog rau hauv av liab qab. Copper conductors yog annealed (mos) tooj liab. Stranded conductors yog compressed stranded. Cov hluav taws xob rwb thaiv tsev yog 90 degree-rated polyvinyl chloride (PVC), nylon tsho.
Hom NM-B yog tsim los kom yooj yim rub, Ua rau yooj yim installation. Lub tsho cable yog xim-coded rau kev txheeb xyuas qhov loj me; White - 14 AWG, Yellow - 12 AWG, Orange - 10 AWG, and Black - 8 AWG and 6 AWG.
1. Jacket: PVC, nplaim retardant. 90 degree.
2. Kev sib dhos: tus neeg xyuas pib nteg nyob rau hauv parallel, nrog kraft daim kab xev qhwv.
3. Wrapping: kraft daim kab xev hla lub grounding conductor.
4. Core Jacket: Nylon
5. Rwb thaiv tsev: PVC, hom THHN.
6. Tus neeg xyuas pib: annealed tooj liab, ua raws li ASTM B3.
