Saw this on reddit. Can anyone confirm it's true.

[Coppersmith]

Saw this comment on Reddit
"the mechanical terminals for most residential devices are not rated for stranded wire".
True or not?

 

[tom baker]

What is a mechanical terminal?

 

[Coppersmith]

I believe he was referring to the screw terminals on a switch or receptacle device. It was a discussion about why stranded wire is not widely used in residential work.

 

[texie]

I'd have to do some digging for the accuracy of this, but I say this is not true. Seems like I or we here have been down this road before.

 

[Tulsa Electrician]

You will find your ansawer in the UL white book.
Look at recpt and snap switch. You may find it interesting.
Also check the instructions for the devices your using.

 

[Tulsa Electrician]

I had this issue with an AHJ.
Here is what I sent him.
They were trying to enforce crimps.
In our case they no amendment stating such use and there was no job spec.

 

[Tulsa Electrician]

Since I mentioned it.

 

[steve66]

This standard commercial spec grade hubbell receptacle can use stranded wire:

https://hubbellcdn.com/specsheet/WIRING_BR15R_spec.pdf

It's the first receptacle I found, so I think its unlikely that "most" do not allow stranded wire.

Also, I've never seen these before:

Hubbell

www.hubbell.com

 

[kwired]

You will find your ansawer in the UL white book.
Look at recpt and snap switch. You may find it interesting.
Also check the instructions for the devices your using.

I know this topic comes up every once in while on this site. The answer always is nearly all of the can be used with stranded conductors, and IIRC the white book almost always was mentioned as a reference on this.

 

[dkidd]

UL RTRT

Terminals of the wire-binding screw, setscrew, or screw-actuated back
wired clamping types are suitable for use with both solid and stranded
building wires.

 

[roger]

So stranded for receptacles yes, switches no unless marked for use with.

 

[tthh]

https://www.leviton.com/en/docs/L-300_B_StraightBladeDevices_2015_Q2j.pdf

"BR-20W Back-wiring clamps accept up to #10 solid or stranded copper wire"

I would guess all the back wire devices probably are rated for that.

 

[roger]

https://www.leviton.com/en/docs/L-300_B_StraightBladeDevices_2015_Q2j.pdf

"BR-20W Back-wiring clamps accept up to #10 solid or stranded copper wire"

I would guess all the back wire devices probably are rated for that.

UL makes a point of stating receptacles can use solid or stranded but switches have to specifically be marked for stranded in order to use the wire binding type terminations for stranded conductors.

 

[VirutalElectrician]

I believe "back stab" type contacts are NOT rated for stranded wire. As the clamping mechanism would force the strands to spread out and not clamp properly. But it's been a long time since I installed a back stab capable device. They are generally low end devices.

 

[Tulsa Electrician]

I know this topic comes up every once in while on this site. The answer always is nearly all of the can be used with stranded conductors, and IIRC the white book almost always was mentioned as a reference on this.

Good to know thanks.
I will do a search and read out of curiosity.

 

[GoldDigger]

I believe "back stab" type contacts are NOT rated for stranded wire. As the clamping mechanism would force the strands to spread out and not clamp properly. But it's been a long time since I installed a back stab capable device. They are generally low end devices.

1. Some back wired receptacles actually clamp onto the back wire using the side terminal screws to compress an internal clamp. Not actually back stab.
2. Where there is an issue with stranded wire is that most terminals that accept stranded wire do not allow use of fine stranded wire. Generally not an issue in residential wiring though.

 

[retirede]

1. Some back wired receptacles actually clamp onto the back wire using the side terminal screws to compress an internal clamp. Not actually back stab.

I’ve always differentiated the two by terms “back-wired” vs “back-stabbed.” I’m not sure how pervasive that distinction is.

 

[jim dungar]

I’ve always differentiated the two by terms “back-wired” vs “back-stabbed.” I’m not sure how pervasive that distinction is.

Industry slang often gets in our way.

UL calls these back-wired and 'push-in' according to the info in post #6, above.

 

[kwired]

UL makes a point of stating receptacles can use solid or stranded but switches have to specifically be marked for stranded in order to use the wire binding type terminations for stranded conductors.

Wonder why? Not really much for construction differences in the components that matter here.

I've been using stranded conductors on both for many years and almost never had any problems. More recently have gone mostly to "back wired" devices with the pressure plate terminals, and is faster install IMO for both solid and stranded.

 

[Tulsa Electrician]

Some pics