Can someone tell me which rule dictates that only one grounded or ungrounded conductor can be secured under a terminal fastener? I can see it being a workmanship issue, but I've yet to find a ruling against it. I often find breakers, fuses and lugs with more than one wire connected.

We have it in NEC 110.14.
Terminals must be identified for use with more than one conductor.

I would imagine that Canadian Code must be similar.

If you have access to, look in the IEC 60364 Sec. 526. I do not have a copy, just a NEC cross reference. Let us know what you find out.

Under B.C.Amendments
(www.safetyauthority.ca/files/Amendments%20to%20Electrical%20Code.pdf) 12-116 reads as follows:
(Italic are added subrules from the amendments)

12-116 Termination of conductors (see Appendix B)
(1) Connection of conductors to terminal parts shall be made by means of pressure connectors, solder lugs or
splices to flexible leads.

(2) The portion of stranded conductors to be held by wire-binding terminals or solderless wire connectors shall
have the strands confined so that there will be no stray strands to cause short-circuits or grounds.

(3) Stranded and solid conductors No. 10 AWG and smaller shall be permitted to be connected by means of
wire-binding screws, or studs and nuts that have upturned lugs or equivalent.

(4) Stranded and solid conductors larger than No. 10 AWG shall be terminated in solderless wire connectors or
shall be permitted to be soldered into wire connectors specifically approved for the purpose except where
prohibited by Section 10.

(5) Terminals for more than one current-carrying conductor shall be specifically approved for the purpose and be
so marked.

These are B.C. Amendments I don't know about Ontario.

Some of you have it pretty well defined in your codes. Maybe there is an Ontario supplement that I'm unaware of. Hopefully someone will come up with a rule number for me if one exists.

I couldn't find anything in the codebook specifically about it but it does say you can't cut strands off to make stranded wire fit. I found the page for Ontario code:
http://www.esasafe.ca/Corporate/gr_004.php?s=8

Doesn't have any amendments to Section 12 that I can see.

This is not a CEC Part 1 issue, it is a CEC Part II issue instead. The individual devices used to terminate connections, switched, receptacles, circuit breakers, etc. will be certified to a Part II standard.

If the device is certified to have two wires under one screw, as in some duplex receptacles and some circuit breakers, then it is acceptable to have more then one wire under a terminal fastener. If the device is not approved for multiple conductors under a single connection point, then it is not permitted.

In panel boards the bonding terminals are approved for 2 #14 or 2 #12 Cu and 2 #12 and 2 #10 aluminum wires. This information is on the piece of paper that came with the panel you throw away without reading. Neutrals are approved for only 1 conductor.
4-026 also requires that you should be able to disconnect only 1 grounded circuit conductor (neutral) without disconnecting the neutral from any other circuit. A terminal with 2 neutrals if loosened to remove 1 wire would possibly open the other.

Rick & Mike

Mike, I'm aware of what you're saying and I agree with your comment.

Rick, I wondered why you wrote with such confidence. After checking your profile and finding out that you are an inspector, I then realized why. I accept the information that you've shared but it's unfortunate that we have to assume it. I would of liked to have seen my answer more clearly/specificaly addressed in the code. There are too many others out there who are taking it for granted that it is acceptable to stick as many wires under a breaker or fuse terminal and it would be nice to just be able to state a specific code ruling clearly stating why it is unacceptable to do so. Thanks for the clarification.

Yes we are lucky to have 2 Electrical Inspectors on the Canadian forum here.

Hi there CS...

Yes, I can see why having it spelled out in a perscriptive code, such as the CEC, would be expected.

Personally I like the BC amendment, but I would remove the phrase "current-carrying" from the BC amendment so it would cover all conductors and not just current-carrying ones. If you are going to add a jurisdictional amendment, it had better address all possible scenarios.

My boss, the Chief Inspector for this jurisdiction is the chair of the CEC Part I Section 2 technical committe and he has explained this issue to me this way...

The thought of the CEC code body is that if an installation issue is made unacceptable via a Part II certification standard, then there is no reason to add additional rules to a Part I section as the complete CAN/CSA C22.1-06 code really consists of all three parts and they need to be applied together to an installation in harmony.

The point is valid and I support it. Having said that, given the lack of emphasis the Part II section sees on a regular basis, perhaps the BC approach is wise.

Thanks for the insight Rick. In response I would like to share the following 2 points:

1) I'm not quite sure of what you mean by "lack of emphasis the Part 11 section sees etc.". If I'm reading it correctly, you may find it interesting to know that the inspector who ran the Master's course, that I attended in the fall of 2006, had to get clarification from his superior before he was able to explain to the class what exactly Section 11 was. I understand that he has been an inspector for quite some time and I thought he was pretty competent. Every day we learn something new.

2)I personaly see nothing wrong with the mechanics of having 2 conductors under one terminal clamp (like a breaker has) if it is done with care. I don't do it simply because I've always been told that the code doesn't allow it. I also would not agree with having common conductors doubled up. Having made my statement about the mechanics of it, I would like to know why you think that the ruling should also pertain to non current carying conductors (ground wires I assume?). I think it's wrong enough that it pertains to the hot conductors as it is. There surely must be some good reason I suppose.
I look forward to your reply.