- Location
- Bremerton, Washington
- Occupation
- Master Electrician
I have seen copper foil on generator fine stranded terminations.
NEC 110.14 and highly stranded wire on oven
- Thread starter tajalir
- Start date
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Polaris makes connector listed for fine stranded wire
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
Right, the grey top ones, see post #2. Anyone know how they differ inside from the normal black top ones?
Cheers, Wayne
curt swartz
Senior Member
- Location
- San Jose, CA
- Occupation
- Electrical Contractor
Not sure what other internal differences there are but the conductors go into a tin plated copper ferrule so the set screw is not directly contacting the strands.
Thank you very much. This is a lifesaver. I have been looking in vain for something like this. Google's AI did not come up with it.
No. They are not. I checked with the manufacturer.
I should have said every double-oven. That is the unit I have. I have a range in the apartment and it has a cord and plug.
It is typically AWM, 105C.
Not so. The way UL tests the connectors, they only use Class B and C strands. If the connector is to be used on other classes (high strand) the connector must be tested and listed that way. Typical connectors in the market are only rated for Class B and C. That is why NEC requries the connector to be "identified" for highly stranded wires if it is to be used that way.
That is correct
The wire nsut specs are confusing in many ways. NEC is very specific about highly stranded wire and the connector requirement.
Yes. That is how it comes - with high-strand wires in a flex conduit from the factory. One manufacturer (forgot which one) even said in its installation manual that you should not replace the whip (flex) with a cord and plug.
That is correct. The connector must be "identified" as suitable for highly stranded wire.
That is the problem I had. But Wayne (above) solved it. NSI manufactures it. But it is pricey.
I have been puzzled by the fact that this problem has not been getting more attention in the past. I believe that highly stranded wires are routinely connected to regular (Class B and C stranded) wires with wire nuts that are only "suitable" for Class B and C strands. Why does this not get attention from the AHJs? I reached out to two AHJ's (chief electricals), and they do not seem to be aware of it. So at first I thought I was losing my mind (which I have, according to the wife). But the more I look at this (and reading UL486, the standard for connectors), I am convinced that manufacturers of connectors only test with Class B and C strands. So the NEC article makes sense.
It’s likely that inspectors never see the connections. At rough-in, all they see is the premises wiring in the box. At final, the oven is already installed and they aren’t going to ask to have it removed.
Fred B
Senior Member
- Location
- Upstate, NY
- Occupation
- Electrician
I Haven't seen a highly stranded flexible cord or wire on a range or oven that didn't have a fork crimped terminal for attaching. Most every oven or range I've seen has a terminal block for attachment of supply wiring to the equipment. Only time I've seen a wire nut attempted was someone damaged the factory installed terminal block. Such I believe then becomes a listing violation. Internal connections were all high temperature crimps for the flexible stranded wire.
Have seen someone try to use a welding cable for a generator hookup and use wire nuts. In bottom of enclosure and hanging off the nuts were several sheared strands of the cable. So how many strands of a 50A rated flexible cable that can be removed before it's capacity has been compromised. Correct answer is probably -0-.
Have seen someone try to use a welding cable for a generator hookup and use wire nuts. In bottom of enclosure and hanging off the nuts were several sheared strands of the cable. So how many strands of a 50A rated flexible cable that can be removed before it's capacity has been compromised. Correct answer is probably -0-.
busman
Senior Member
- Location
- Northern Virginia
- Occupation
- Master Electrician / Electrical Engineer
I believe you are correct for ovens and ranges. I have installed quite a few cooktops that came with a Greenfield whip and free conductors (finer than B or C).
Mark
curt swartz
Senior Member
- Location
- San Jose, CA
- Occupation
- Electrical Contractor
Wall ovens and cooktops always come with whips, never terminal blocks.
Wire-nuts may not be listed for the connection but they have been the standard connectors used for 60+ years. I have never run across a problem unless the wrong size connector was used or wires were not stripped long enough.
Wire-nuts may not be listed for the connection but they have been the standard connectors used for 60+ years. I have never run across a problem unless the wrong size connector was used or wires were not stripped long enough.
You have a good point. I agree that wire nuts are being used in practice to connect these. As to the fact that there has never been a problem, I am not sure. Typically, the way requirements get into the NEC is when something burns up. The point gets raised with the Code Making Panel and they write a rule. There are some areas in NEC that are hard to enforce. Torque on the connections is another area that is hard to enforce, so it gets ignored. But I am not sure if any of this makes it right.