OK to use ring terminals on breakers?

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Old 02-09-13, 07:54 AM
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OK to use ring terminals on breakers?

I am installing a sub panel and will be connecting a generator transfer panel into those circuits. The breakers are the type where you normally slip the solid romex wire under one side of the screw head and tighten the screw down.

The wires from the transfer panel are stranded and when I initially connected the wires to my circuits on the main panel back when I purchased it, I didn't like the way the stranded wire spread out under the screw head, even when looping it around the whole head in the proper direction.

I would like to use the crimp on ring terminals for a cleaner connection but was wondering if that is an acceptable practice.
 
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Old 02-09-13, 08:37 AM
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Unfortunately it is not. There are no such terminals listed for use outside of an already listed assembly (a control switch, an appliance, etc). Using them will cause you issues down the road if it needs to be inspected.

First of all, normally on a breaker listed for use with stranded wire, the wire does not go under the screw head. There is a pair of pressure plates under the screw, and you are supposed to sandwich the wire between them. Since the plates stay steady when the screw turns, the strands should not fray out.

The proper practice for wrapping stranded wire under a screw head is to twist the strands COUNTERclockwise (the natural way if you're lefty) before bending it around the screw.

Alternatively you can pigtail a short length of solid wire to the stranded.
 
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Old 02-09-13, 08:45 AM
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Makes sense. Since I don't have the type breaker connection you describe with the plates which I have seen, so I know what you mean, my other thought was to tin the wire ends with solder and just stick them under one side of the screw head like the solid romex wire. Would that be acceptable? I can go the pigtail route, but figure the less splicing the better if I can avoid it.
 
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Old 02-09-13, 09:16 AM
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Solder is a bad idea, when it is compressed, since it will flow and could cause a low force connection, and then melt away with the induced heat. Not good at all.

When I designed industrial wiring in cabinets, I speced in ferrules to go OVER the bare strands and then crimped with the suitable tool. Not to be confused with a PIN crimp terminal, which extends the wire to a rolled copper pin.

I might also take JM advice and splice a solid wire to the breaker.

I'm a bit surprised you can't take pliers and wraps the strands tight enough to make it work. What AWG?
 
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Old 02-09-13, 09:19 AM
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While soldered wire-to-wire connections are allowed, I don't think tinning is acceptable. Mainly because a tinned stranded wire under pressure of a mechanical clamp has a tendency to 'cold flow' (deform), which leads to loose connections and could result in the joint getting hot and causing a fire. This is the same phenomenon that causes aluminum clamp joints to loosen and cause fires over time, and why aluminum joints have torque specifications.. As soft as copper is, it is still harder than aluminum, and it is much harder than the tin and lead or silver in solder.

Try twisting the strands counterclockwise.. You might be surprised at how well it works. Another trick is to strip the strands longer than needed, but do not pull off the tail of insulation all the way off. Use it to do the counterclockwise twist, then wrap the wire around the screw and tighten it - with the insulation tail still on to keep the strands neat while the screw tightens.. THEN use a pair of nippers to cut the tail off flush with the screw.

Could you post a pic of the clamp on your breaker?
 
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Old 02-09-13, 09:21 AM
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Matt.....it's probably the breakers that use a screw and have a slight indent in the one plate on the breaker side.

(like the old Square D in the pic)
 
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Old 02-09-13, 10:48 AM
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Thanks for the advice guys. Goes to show me my "McGuyver" solutions aren't always the best, :NO NO NO:. I'll play it safe and use a 12ga romex pigtail and wire nut. For some reason, I hate wire nuts even though I can't say I ever had a problem with one. I think my fear is the possibility of getting a poor connection with the wires and I end up tightening them until the wires start to twist and then tape the heck out of them so they can't fall off. Yes, I am an individual prone to mild anxiety at times
 
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Old 02-09-13, 11:20 AM
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Here's a picture. Not the best, but you can see there is nothing to hold the wire except the head of the screw. The panel is a Crouse Hinds installed in 1983 and some of the breakers could be older than that. The red wire is the stranded one from the switch panel and above it is a normal romex wire from a circuit not on the switch panel.

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Old 02-09-13, 11:27 AM
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I would use pieces of individual conductor rather than Romex, and I would fan the stranded conductor slightly to lay along the solid wire and use the wire nut to make the connection. I would also only use #12 AWG wire on 20A circuits, with #14 for the 15A circuits.

If you trim the conductors and the insulation to be even and fit inside the wire nut, then tightening by hand should be sufficient. I never tape over a wire nut - serves no purpose, IMO, and is a PITA to get off later. That said, I'm kinda picky about which wire nuts I prefer to use, and I always end by positioning the splices to point up into the wire nut. In a panel, I would grab a handful of the wire nuts with the rubber skirts, from 3M.
 
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