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My AWG 8 (or maybe 6?) wire used to be on a 50 A breaker. It's stranded (4 copper strands). I'm replacing the breaker with a 30 A one (appliance requires it). I wonder if the connection below is acceptable, or if I need a piece of solid wire and a nut.

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Edit: following the accepted answer, I redid it on the proper side of the metal tab.

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9
  • What make/model is the new breaker?
    – ThreePhaseEel
    Oct 23, 2022 at 14:59
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    Eaton QBH 230, in a commander BC panel
    – Jeffrey
    Oct 23, 2022 at 17:05
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    That connection doesn't look right to me -- the screw doesn't seem to catch all the strands, but instead mashes them and spreads them apart. Shouldn't the wire be trapped under something? Is that a movable plate or clamp behind the bare strands?
    – A. I. Breveleri
    Oct 23, 2022 at 19:25
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    @RedSonja "tin the ends" is bad. Tin "flows", it slowly deforms under pressure, making a bad contact when compressed by the screw terminals. Bad contact with high current generates heat, and that is bad.
    – Martin
    Oct 24, 2022 at 9:22
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    @RedSonja See my answer in the bottom. Either use the right clamps or wire ferrules
    – Martin
    Oct 24, 2022 at 11:11

3 Answers 3

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You need to redo those connections. There is a flat plate in the connection that should be above the wire and in contact with the screw. The wire should be between the flat plate and bottom of the connector with the screw forcing down the plate on the wire. Yes, stranded wire can be used in this breaker.

My "plate" moves with the screw so you'll have to check yours out.

(Adding as an edit) This is the plate being mentioned here. It should be between the wire and the screw:

Plate

Also make sure you followed the wire stripping gauge on the breaker and inserted the wires far enough into the breaker. Some breakers have a "frame" in the back of the connection to hold the wires in place so the screw doesn't spread them apart when torqued properly.

enter image description here

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  • How tight should the flat plate be? I wondered about that and tried to lift it. It didn't seem to move. I didn't want to force it, because this breaker model is very hard to find (The Eaton rep told be about many hundred units waiting to be filled, so I bought an used one.). But hey, ok, I'll try again next week when I go back (the appliance is not in use in the meantime)
    – Jeffrey
    Oct 23, 2022 at 22:02
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    @Jeffrey the plate shouldn't be tight, mine moves with the screw but yours doesn't. Either way, redo them, wind the strands together and center them under the screw if plate doesn't move and torque according to breaker instructions. Not a fan of used breakers.
    – JACK
    Oct 23, 2022 at 22:31
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    Maybe, @Jeffrey, your used one is also defective...
    – FreeMan
    Oct 24, 2022 at 0:00
  • @Jeffrey: the official tightness is in the spec sheet for the breaker, and will be specified as a torque value. For some brands that info may also be in a label on the box somewhere. Pros seem to just learn what feels right;.for wiring my workshop I paid for a torque screwdriver so I could be sure I was getting it right. (See ThreePhaseEel's answer).
    – keshlam
    Nov 20, 2022 at 3:19
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The QBH230 should have no trouble accepting 6AWG wire

According to the Eaton Canada distribution catalog, the QBH230 can accept wire as fat as 2AWG, so your 6AWG wire should not be an issue. If it appears to be one, it's best to undo and redo the connection, ensuring that you use a torque screwdriver to set the lug torques correctly.

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4
  • The stranded/solid makes no difference?
    – Jeffrey
    Oct 23, 2022 at 17:53
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    Correct. At larger sizes, solid isn't even avaliable
    – manassehkatz-Moving 2 Codidact
    Oct 23, 2022 at 17:58
  • @A.I.Breveleri -- yeah, the black wire might be a bit overtightened
    – ThreePhaseEel
    Oct 23, 2022 at 19:25
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    At larger sizes, you need hydraulics to bend solid-core wire!
    – FreeMan
    Oct 24, 2022 at 0:01
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Nothing wrong with this. They also make fork spade connectors for this purpose, but there is absolutely nothing wrong with using stranded in breakers. This goes for grounds, hots or neutrals.

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2
  • 2
    This is very much a North America/US looking breaker and fork/spade/ring connectors aren't allowed by the NEC.
    – FreeMan
    Oct 24, 2022 at 15:47
  • Which is why you just use stranded wire!
    – Paebak
    Nov 4, 2022 at 13:24

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