"Side" Vs. "Back" Mounting Of Typical Wall Switch ?

[Bob]

Hello,

Always good to learn something:

Have to replace a 3-Way wall switch for my basement lights. So, went to HD and bought a Leviton 3-Way switch.

Surprised to see thast they don't, apparently, come with the holes for putting in the wire anymore. The holes used to have an internal pressure clamp, so all one did was strip about 1/2 of insullation off the No. 14 or No. 12 wire, and push in the hole.

There was also a small place to push if one wanted to remove the wire for some reason, later.

Now, they seem to have two options; the "side" or "back mounting" ones.

In one, you just loop the wire around the screw head, and tighten. That's fine, but the flat part of the screw head isn't all that big.

In the other, you keep the bare wire straight, and just push under a clamp that is built in, below the screw head, and tighten.

Which technique is used more these days ? Why ?

Pros and cons for each ?

etc. ?

Thanks, Bob

[Mayayana]

"Bob" wrote

| Surprised to see thast they don't, apparently, come with the holes | for putting in the wire anymore. The holes used to have an internal | pressure clamp, so all one did was strip about 1/2 of insullation off | the No. 14 or No. 12 wire, and push in the hole. |

Good riddance. That's a lazy method that doesn't make a proper connection and can be prone to sparking. It needs to loop around the contact screw and should then be taped. The screw head may not be as big as you'd like, but if you loop the wire around you'll see that there's no way for the wire to slip out (or to be put in) until the screw is backed out most of the way. The sides of the surrounding plastic block it. So as long as you actually loop it around and don't just stick it under the screw, then a tightened screw can't fail to make a strong connection.

[HerHusband]

Hey Bob,

Those spring holes were notorius for making bad connections. Wires could slip out if the spring weakened, the outlet could arc, the clamp could cut into the wire and cause it to break, etc. I believe they are now banned by current electrical codes?

The standard screw works fine if you wrap the wire around the screw in the direction the screw turns when you tighten it. It makes a nice strong connection. Just make sure the wire is stripped back enough so the insulation is not under the screw, but not so far that you have bare wires beyond the screw.

The clamp style works nice also, especially with heavier gauge wire that is hard to bend around a screw (10 gauge and larger). Slip the stripped wire under the clamp and tighten down the screw.

Anthony Watson

[gfretwell]

The code never addressed it either way. It is all in the listing and U/L lifted the listing on back stabbers for 12 ga wire. They are still legal for #14. If you have an older one that still says 12 or 14, the inspector would be hard pressed to reject it.

[anonymous]

Bingo!

[DerbyDad03]

But the homeowner should.

[clare]

Definitely easier to do it "right" with the back clamp - easier to do it "wrong" with the "loops"

[clare]

True - but you would be foolish to use it, since they have been proven to be a safety risk

[gfretwell]

Do you have a cite for all of the fires and deaths?

[clare]

Not for "fires and death" but definitely for scorched wires and blackened devices (usually outlets, but occaisionally switches as well). My dad was an electrician most of his life and he cursed those things particularly when using an outlet as a "feed through" instead of pigtailing (a very common practice). How many fires caused "by an electrical fault" could be attributed to those bad connections I have no idea.

[gfretwell]

The UL/CSA listing does not say a device will not fail, only that the fire will be contained in the box. The evaluation of the device determined that most of the time, it was the insertion force of jamming the wires in the box that deformed the spring contact so they limited it to 14ga wire, that bends easier. It also helps if you bend the wire flat to the device and form the zig zag before you push them into remove the sideways force. I don't like stabs and I would not use them myself but they are still legal with 14ga wire.

[clare]

There are a lot of things that are legal, but far from adviseable. If the box is anywhere near reaching the allowable wire fill it is virtually impossible to install the device without putting a stress on the connection. You are gambling whether that stress is "safe" or going to cause a problem. If there is an advantsge the "prudent" thing to do is take the alternative course. ALL backstab devices also have side screw connections (I'm talking outlets and switches, not push-in wire connectors etc) so it is better to use them - or for the price of a new device, get a new back-clamp device which has the advantages of both side-screw and backstab without the drawbacks of either.

[HerHusband]

Hmm.. I thought I heard they were no longer acceptable. My mistake. Thanks for the correction.

I used those back stab connections when I first started doing electrical work. I didn't think much of it until a few outlets quit working and I tracked the problems down to the back stab connections. I don't trust them and haven't used them since.

Anthony Watson

[gfretwell]

I think we all agree the reliability is shaky but this is what the

2014 U/L white book says about terminals. (RTRT)

Screwless terminal connectors of the conductor push-in type (also known as ??push-in-terminals??) are restricted to 15 A branch circuits and are for connection with 14 AWG solid copper wire only. They are not intended for use with aluminum or copper-clad aluminum wire, 14 AWG stranded copper wire, or 12 AWG solid or stranded copper wire.

Single and duplex receptacles rated 15 and 20 A that are provided with more than one set of terminals for the connection of line and neutral conductors have been investigated to feed branch-circuit conductors connected to other outlets on a multi-outlet branch circuit, as follows: Back-wire (screw-actuated clamp type) terminations with multiple wire-access holes used concurrently to terminate more than one conductor Side-wire (binding screw) terminals used concurrently with their respective push-in (screwless) terminations to terminate more than one conductor

Single and duplex receptacles rated 15 and 20 A that are provided with more than one set of terminals for the connection of line and neutral conductors have NOT BEEN INVESTIGATED to feedbranch-circuit conductors connected to other outlets on a multi-outlet branch circuit, as follows: Side-wire (binding screw) terminal with its associated back-wire (.screw-actuated clamp type) terminal . Multiple conductors under a single binding screw Multiple conductors in a single back-wire hole

Duplex receptacles rated 15 and 20 A that are provided with break-off tabs may have those tabs removed so that the two receptacles may be wired in a multi-wire branch circuit or multiple branch circuits.

[TomR]

Good information. Thanks for posting it. I never really liked the push-in spring-type back wire connections, and I have noticed that the only ones that I see on store shelves are for 14 AWG only. Now I see why -- they stopped the 12 AWG push-in connections.

I do like the "regular" "side and back wire" outlets that allow the wire to be pushed into place from the back and then screwed down tight with the screw on the side. I like them when using 12 AWG wire because it seems easier to do the installation and get all of the wires and the outlet back into the box.