I’ve been wondering about this for a while – what’s with the loose screw terminals on a GFCI receptacle? You know, the kind that are wobbly when they’re loose and don’t stay out, but still tighten down OK. The screws on regular receptacles stay put when you loosen them, so wiring is easy, but on a GFCI I always wind up holding the thing upside down or on its side to get the wire hook around the screw. It’s not too bad on a single-gang, but by time all the wires are connected on a double gang box, it’s tough to get the thing to actually turn on its side. It’s quite a pain in the neck. One advantage I see is that they make for easier straight wire connections from the rear without relying on spring connectors, but everyone still says to hook the screw terminals instead of straight connections. Are there any tricks for hooking the screw?
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Bill,
I think you answered your own question: they make for easier straight wire connections from the rear without relying on spring connectors.
~Peter
I get up in the morning and drive to Home Depot. I work there from 7 to 3:30. Then I go home.
Right, but I'm always hearing everybody say don't use the rear connections, make the hook and screw it down, for maximum safety. Makes sense to me, even without the springs, a crimped hook has a physical connection a clamp can't match.
So it's perplexing to me that they would make the preferred method so stinkin' hard to make the non-preferred method only marginally easier. If they had regular screws, all you'd have to do to use the rear connectors would be to loosen the screws a little bit before sliding in the wire. 10 seconds per receptacle, maybe?
Usually when I'm perplexed like that the manufacturer isn't crazy - I'm just missing something.
Thinking about it some more, I should check around and see if there are any manufacturers who offer a GFCI receptacle with regular screws. If they want my business that's a good way to get it. :)
These are not the same type as the evil back stab connections folks are talking about. They give full contact for the wire to the terminal. These are designed to be wired sort of like you do the feed wire from a circuit breaker. Looping the wire and putting it under the screw is not the way they were designed to be used.
Edited 2/11/2004 11:43:37 AM ET by RASCONC
Exactly. Not all back wiring methods are the same. The ones operating on a the spring tension of a thin piece of phosphore bronze, you can tell which ones they are as they have a small release hole so you can pull the wire back out.
These are viewed, by every electrician I know who deserves the title, as abortions. The only up side is that they guarantee service calls as they wear out. As long as people keep putting them in like this there will always be service calls to fix them. $.
The clamps are very good, as good in my estimation as a wrapped-screw connection, as long as they are tightened firmly. They are just a bit faster than wrapping the screw but most of this saving is usually wasted. I'm so used to automatically forming a hook to connect devices that I have to restraighten the wire and take off a bit. Makes it a wash.
Clamping with pressure plates is a long accepted as a preferred method. It is very, very common in industial control systems.
And used in many circuit breakers.
Just not seen in most home wiring unless you go with some of the more expensive devices.
Great, thanks guys!
Just be sure to snug those clamps up tight. This tightness is easier to spot on a wrapped screw. It is open and you can actually see the copper flatten slightly as it comes up tight. The Clamps are typically hidden and you need a firmer hand to get the same result.
A common problem is getting the wire on the wrong side of the moving plate. Always face the screw up, a bit of a shake helps also, before inserting the wire
I usually save a few defective GFIs and let the helper strip a couple to see how much torque the clamps can take. On some brands it is quite impressive. You have to try to strip them so few worries if a little care is taken.
Only clamp type connections I can remember failing are ones that were not tightened sufficiently. Some of the clamp screws can be stiff and people sometimes give up too soon thinking the connection is tight. Experience helps greatly. A firm yank on the wire also helps confirm a good connection.
Good point. Maybe this is obvious to most, but I figured since I was trying the back clamps I'd really get the screws nice and tight with the cordless driver.
Just to be sure I double-checked with a standard screwdriver.
Turns out the electric phillips cams out before the screw is all the way tight. I got at least a half turn extra out of the hand screwdriver, and that's just what I'd call tight, it wasn't excessive effort.
Using the "backwired" approach where the screw compresses a plate onto the wire is far superior to either the wrap-around-the screw technique or the "back-stab" technique (which should NEVER be used). I will, when possible, spend the extra money to buy back-wired components, both for ease and reliability.
1. GFCI do not have poor spring connectors like found on outlets.
2. GFCI have reliable clamp connectors in the back.
3. If you want to put the wire directly on the screw terminal,
you can disable the clamp connector by forcing a piece of 14awg wire
behind the clamping plate. This will reposition the threaded plate up to the screw.
4. Why do I know this?
Marine rules require stranded wire with a ring terminal on the screw.