Sub panel feeder line

[Ellement]

Hi,
I have an old GE 240v, 200-amp breaker panel that breakers are no longer available, so to add extra circuits and avoid changing the 200A main panel I want to install a sub panel.

My question is that being these breakers are almost impossible to find let alone a 2 pole 60-amp or 100-amp, I?ve been told I can secure the #6 or #3 feeder wire to the sub panel on to the main panels lugs of the 200-amp main panel? There is a separate 200-amp disconnect switch supplying the 200-amp main panel. Now I?ve seen this done before when there is limited room in the main for a sub panel feeder breaker but I have a hard time accepting that a 200-amp rated #3/0 can be squeezed together with a # 6 or #3 into the same lug, or adding a double lug on the main, that would be better, but is that considered modifying the panel?

As well if this is possible to feed a 100amp panel from a 200amp bus do I need a main disconnect in the sub-panel.
Thanks in advance.

[twh]

I'm having a little trouble picturing the panel you are talking about. I called gescan and was told that if it's a bolt-on, it hasn't changed from day one. If it's a push on, the THQL style breaker should work. How old is this panel?

The options you describe don't excite me very much, either.

[electricguy]

How were you planning to protect the smaller conductors? is the 200 amp disco fuseable?

[neil seidner]

Since the "main panel" is feed from a seperate 200A disco (presumeibly fused at 200A), the main panel is not in terms of the CEC considered to be the service equipment. This means you can ignore anything in section 6.

Since the smaller (#3 or#6) is not properly protected by the 200A fuse, it is not actually considered a feeder, but is rather considered a "Tap Conductor". Therefore the conductors must conform to requirements of 14-100 in terms of conductor length and size, wiring method, and downstream O/C protection (yes you would need a "main breaker" in the sub panel)

Two conductors in a lug that is rated for one conductor is a code violation. Changing wrong lugs and installing right lugs is not a code violation.

[Ellement]

Thanks for your response guys,

Yes, it?s a fused 200 amp disconnect?

More details:
It?s a 100 year old home, with the main 200amp feed run in BX through 20ft. of crawl space to the back wall, not your conventional hook-up. The main panel is a (I will verify), but nevertheless, this out of date panel is an issue, and I?ve been told that only used or old stock breakers are available. Old wiring is tied into this panel so replacing it would be a nightmare. To me the least costly and labour intensive way to deal with the addition of new circuits is to add a sub-panel, as far as safety and code, I hope you can point me in the right direction.

I also think rule 14-100 (b) & (c) will allow my suggestion of a smaller conductor feeding off a larger supply bus/terminal. Just wondering how would be the best way to tie the smaller conductors to the main 200amp bus terminals without too much modification. Would adding an additional lug under the existing lug be possible, or is there a dual lug that I can use that won?t jeopardize the integrity of the main panel?

Thanks again.

[twh]

I'll go with Neil on this one, and you should use a double barrel lug. Changing the lug shouldn't be hard, unless it's attached with a stud that is too short.

[thomas88]

If I understand what is being said in this thread, you are running a #3 wire to a sub panel, with a 200-amp fuse on it and a 100-amp breaker in the sub-panel on the load-side of the wire.

Does this mean that the wire which is rated to about 100-amps is fused at 200-amps? So if this wire shorts somewhere between the two panels, you are going to need a lot more current to interrupt the circuit than the wire is rated for. I would have thought that you would have needed the wire running to the sub-panel rated for 200-amps if you are connecting it directly to the bus in the main panel without a breaker.

The reason I ask this is I have two panels in my house. One 200-amps, and a sub-panel at 100-amps. Currently there is a 60-amp breaker in the main panel feeding the sub. The sub has a main breaker of 100-amps. Since the load in the sub-panel can easily exceeed 60-amps (stove, dryer, water heater, etc), I was thinking about upgrading the sub-panel feed wiring (some of which is old, yes including a splice part-way in between).

It would be cheaper for me if I could just get 3/3 wire and connect it to the main bus in the main panel without a breaker (which would save me replacing the 60-amp breaker in the main panel with a 100-amp breaker). From my understanding, this would not be allowed. Can someone clarify this for me?


Thanks!
Thomas

[Ellement]

There are a number of conditions to be met in rule 14-100 that will allow the situation were discussing, it would be best to review them all first.
It's great to be able to field these questions with such an informed and helpful group.

Thanks all...Cheers!

[twh]

Thomas, no. This is about a special situation where there is a fused main disconnect ahead of the panel. You probably have a panel with the main breaker in it. This does not apply to that situation. It is also the less preferred method. You will note that breakers are not available. As to saving money, the lugs may cost as much as a breaker. You're scaring me.