Wiring Receptacles

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
more upside than downside using them from an install standpoint?
I would say marginally yes but I would assume that they're more expensive. It does save on having a guy cut up pigtails. The product we used had stranded wire leads which made it easier to push the device into the box.
 

ramsy

Roger Ruhle dba NoFixNoPay
Location
LA basin, CA
Occupation
Service Electrician 2017 NEC
The feed-throughs are rated for it, and I've simply seen too many 60-80 year old receps that are still in good functioning condition.

UL 498 tests standard receptacles at 150% of rated current,1500 Volts, 1000A fault current, and for Mold stress relief: Unwired receptacles are subjected to 70°C for 7 hours, hospital grade @ 90°C..

Qualified persons expect UL listed feed-thru device lugs to handle idiot proof abuse, but after scolding clients for having 20A or 30A breakers on 15A wire, we don't expect DIY's to do that again.

WIRE CONNECTORS AND SOLDERING LUGS (ZMVV), which include typical insulated wire nuts for pigtails, don't require a UL standard for testing. Rather they are subject to NFPA-70 110.3(B), packaging instructions, labeled for voltage as low as 300 V, and temperatures as low as 75°C.

My service calls are finding more melt downs, burnt, or damaged devices not UL listed, or labeled for Instructions, responsible for tripping A/GFCI's. Its those purple Wirenuts, extension cords, USB outlets, power strips, surge protectors, and charging accessories purchased online, or from thrift stores.
 

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Knuckle Dragger

Master Electrician Electrical Contractor 01752
Location
Marlborough, Massachusetts USA
Occupation
Electrical Contractor
UL 498 tests standard receptacles at 150% of rated current,1500 Volts, 1000A fault current, and for Mold stress relief: Unwired receptacles are subjected to 70°C for 7 hours, hospital grade @ 90°C..

Qualified persons expect UL listed feed-thru device lugs to handle idiot proof abuse, but after scolding clients for having 20A or 30A breakers on 15A wire, we don't expect DIY's to do that again.

WIRE CONNECTORS AND SOLDERING LUGS (ZMVV), which include typical insulated wire nuts for pigtails, don't require a UL standard for testing. Rather they are subject to NFPA-70 110.3(B), packaging instructions, labeled for voltage as low as 300 V, and temperatures as low as 75°C.

My service calls are finding more melt downs, burnt, or damaged devices not UL listed, or labeled for Instructions, responsible for tripping A/GFCI's. Its those purple Wirenuts, extension cords, USB outlets, power strips, surge protectors, and charging accessories purchased online, or from thrift stores.
In regards to the image. It happens in all types of terminations. Probably due to a poorly made splice and possibly moisture trapped in the wire nut
 

ramsy

Roger Ruhle dba NoFixNoPay
Location
LA basin, CA
Occupation
Service Electrician 2017 NEC
That box was used as a combiner junction for a resi-rooftop solar array, which remained energized on me after dusk until all panels were covered in tarps.

That picture was taken after pulling the wire & nut from short-circuit contact with top of metalic box.

Here are the pictures below.
 

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ramsy

Roger Ruhle dba NoFixNoPay
Location
LA basin, CA
Occupation
Service Electrician 2017 NEC
I'm thinking a =>1000 volt Megger Test blew thru this 300-600 volt wirenut, in contact with the bonded metal box, which eventually shorted out at 120 volts.

The insulated plastic exterior of these kind of wirenuts I also find bulging or split from over tightening, or using too large or too many wires.

The prolific use of 300-600 volt wirenuts, per North American UL ZMVV, supports my practice to set Megger @ <=250 volts, and explains why we don't mandate typical 1000+ volt insulation testing during construction.

European visitors to this forum are often confused about this, since their building codes match their equipment listed for standard Megger testing.

I use a 100 volt Megger when A/GFCI devices are in the way.
 

horsegoer

Senior Member
Location
NJ
Occupation
Estimator
Of course there is the situation with receps on a MWBC where it is required to pigtail the neutral to the device.
You would always pigtail the neutral or connect right to the terminals? Or your talking about it HAVING to be pigtailed in lieu of connecting right to the terminals if it's MWBC? If so that's interesting and I would assume code?
 

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
You would always pigtail the neutral or connect right to the terminals? Or your talking about it HAVING to be pigtailed in lieu of connecting right to the terminals if it's MWBC? If so that's interesting and I would assume code?
You must pigtail. See 300.13(B). This is required so that the neutral conductor is not inadvertently interrupted. Otherwise the magic smoke could come out.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
That's similar to the rule against EGC continuity being dependent on device terminations.

Note: Years ago, receptacles were available with two EGC terminals for feed-through wiring.
 

horsegoer

Senior Member
Location
NJ
Occupation
Estimator
You must pigtail. See 300.13(B). This is required so that the neutral conductor is not inadvertently interrupted. Otherwise the magic smoke could come out.
ok read it and see it’s
just for MWBC . i don’t know what you mean by the grounded conductor being interrupted. can you give example ? ty
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Imagine a receptacle on a MWBC with the neutral fed through the terminals, and you, for whatever reason, decide to disconnect one of the white wires.

The handle-tie requirement theoretically makes this need moot, but it's a darned good practice anyway.
 

James L

Senior Member
Location
Kansas Cty, Mo, USA
Occupation
Electrician
ok read it and see it’s
just for MWBC . i don’t know what you mean by the grounded conductor being interrupted. can you give example ? ty
If you have a mwbc (b + r + w) with both circuits feeding out, you have 2 hot wires for each circuit and 3 neutral wires.

I worked at a place in the 90s where a guy had the neutrals all on a device instead of pigtailed.

A different guy got into that receptacle, which happened to feed a big entertainment center. He unhooked all the neutrals first, and the imbalane on the hots sent over voltage onto one of the circuits and fried about $15k of stereo equipment
 

garbo

Senior Member
Do you guys use feed through method( connecting right to terminals) or pigtail/splice the conductors to the terminals? Thanks
In my 50 years sparky career found that pig tailing worked best for 2 reasons. Easier if you have to tap off at that location in the future and every feed thru could cause a problem. If you have 8 receptacles on a circuit and first feed thru wire comes loose then every device is effected. Best practice is to use at least spec grade devices especially in kitchens, bathrooms, room air conditioners etc.
 
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