single phase applied to a 3 phase breaker

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stew

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Just had an inspector tag me for putting a and c phase of a 240 delta service to a 3 phase main breaker in a panel that will be used for only single phase loads. he says the breaker (ch cc3200) is not listed and labeled for this use. He is of course wrong but whats your guys take on this?
 
Who is the inspector to say what kind of loads will be pulled from this service in the future? Surely you must have three-phase into this building for a reason? Tell him that the contractor will eventually be installing 208 V equipment. I don't know if it is required, but it couldn't hurt to have a two-pole main breaker in your single-phase sub-panel anyway.
 
stew said:
Just had an inspector tag me for putting a and c phase of a 240 delta service to a 3 phase main breaker in a panel that will be used for only single phase loads. he says the breaker (ch cc3200) is not listed and labeled for this use. He is of course wrong but whats your guys take on this?
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I dont know where i can start but for starter here .,, is the main breaker is used for both 3 and 1? load ??

is this only load centre box you have or have a extra 3? load centre box as well ??

but IMO maybe the inspecter is right because if you dont have any 3? load in the box you should used the single phase box instead of three phase box.

This topic been brought up some time back with Larry Fine [ if that ok with ya :cool: ] and see how myself and few other was discussing how this can meet the code with it.

Merci, Marc

P.S. Larry if you recall that one can you post the link for us ?? many thanks
 
I believe the inspector is correct in tagging, but not because of the breaker (if in fact that is what he tagged). On panelboards, 408.30 requires manufacturer labeling of the working voltage, maximum current, and number of phases.
 
Smart $ said:
I believe the inspector is correct in tagging, but not because of the breaker (if in fact that is what he tagged). On panelboards, 408.30 requires manufacturer labeling of the working voltage, maximum current, and number of phases.
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Good point. If he's getting a 3φ main breaker in the panel, I assumed that it is a 3φ delta panel, but maybe not since he says he is supplying 1φ loads.
 
lordofpi said:
Good point. If he's getting a 3φ main breaker in the panel, I assumed that it is a 3φ delta panel, but maybe not since he says he is supplying 1φ loads.
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Sounds to me like he's trying to use a 240/120V 3? 4W panel as a 120/240V 1? 3W panel. You can load such a panel with only 1? loads, but it has to be fed with all three phases... doesn't matter whether only one phase is used.
 
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Well, if that's the case, I could definitely see an inspector's eye brow being raised. OP ought to blank out all the 208 slots or very carefully use those with two-pole 240 loads. Either way, it still comes down to "what is the point of 3-phase?"
 
this installation has one 2 panels. one fed with the 120/240 3 phase and one which was sub fed from the 3 phase panel to the other panel with a sub feed 125 single phase feed. the customer has split the unit into two spaces and wants to meter the second panel separatley. I installed a second meter and tapped the service outside in a ct can which is only used as a junction box.(no ct metering here) I brought the a and c phase into the second panel to refeed it. All cutler hammer breakers are not only listed for 1 phase but have a sticker right on them that says "use any two lugs for single phase service" there are only 2 three phase loads in the whole building which are running off the three phase panel adjacent to this one. There is in my opinion no code violation here. . Feeding a 3 phase breaker with only single phase is a very common practice. I have checked with c/h to confirm the approval and will now do so with seimens ge and square d to confirm what I already believe to be true that all manufacturers have thier breakers listed and labeled for three or single .If you stop to think about it in this case especially where all you have is single pole loads what is safer, a and c phase only or putting the high leg into the equation when it is not used or needed?
 
Stew, I agree with you. I have done this configuration many times (kind of wish I knew why :grin: ), and it is absolutely viable and makes sense. I haven't been in the exact situation with the 3-pole breaker that isn't really needed, but I see what you are trying to do, and it makes sense.

I'm sure if you ask the AHJ for a code citation, you will get a "aww, nevermind. Approved." Unless I'm missing something?
 
frenchelectrican said:
This topic been brought up some time back with Larry Fine [ if that ok with ya :cool: ] and see how myself and few other was discussing how this can meet the code with it.

P.S. Larry if you recall that one can you post the link for us ?? many thanks
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Ees okay! :) I'll find the thread if necessary. Technically, it doesn't apply to this thread, since the question here is whether it's okay to use a 3-p MB panel on 1-ph. In my opinion, it should be okay; just don't use the center lug.

In my case, the debate was choosing between a single 3-phase panel and a pair (one 1-ph and one 3-ph) when there was only a single 30a 3-phase load (an existing RTU) and the rest of the building was wired as 120/240v anyway.

I opted for the separate panels: a 125a 3-ph ML panel, using the 6-throw allowance to only have a 30a 3p breaker w/out a main. I supplied this panel with #4 just in case any new 3-ph loads are added.

Plus, the meter base doesn't alllow anything smaller than #4, and the high-leg comes straight from its lug; the A and C phases are tapped from the 200a panel's lines in a separate box below the meter.
 
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stew said:
All cutler hammer breakers are not only listed for 1 phase but have a sticker right on them that says "use any two lugs for single phase service"
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That should satisfy the inspector.
 
Sometimes with situations like that, you can pop a couple of single-phase 240 V loads in that 3φ panel just to make sure that B-phase gets a good workout now and again. With these situations, it is nice to reduce some of the current draw on the other two phase conductors if you can.
 
lordofpi said:
Sometimes with situations like that, you can pop a couple of single-phase 240 V loads in that 3φ panel just to make sure that B-phase gets a good workout now and again. With these situations, it is nice to reduce some of the current draw on the other two phase conductors if you can.
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I'll use the high-leg for a 240v 1-ph load when necessary, but most high-leg services have a reduced b-phase conductor, since they're often fed from an open Delta and the 3-phase load is small.

Many, if not virtually all, open-Delta services originated as single-phase services converted to 3-phase to suit new equipment, or were services installed to conform to existing POCO equipment.

After all, why would anyone specify a high-leg system for a new service? I'll bet you couldn't get your POCO to install a new high-leg transformer bank today; they'll want to supply a Y system.
 
Too true, Larry; I always seem to wind up doing service work on them, but new installs, next to never.

Was this open delta, btw? I didn't remember the OP saying that.
 
120/240 delta bank original system about 20 yrs old. Thid poco of course does not use this system any more. I am still working on getting the other mfgrs comments . It would seem to me that if on of the major mfgrs says it ul listed and approved then all of the others would certainly be ok because they all want to conform to the same ul standards right?
 
stew said:
120/240 delta bank original system about 20 yrs old. Thid poco of course does not use this system any more. I am still working on getting the other mfgrs comments . It would seem to me that if on of the major mfgrs says it ul listed and approved then all of the others would certainly be ok because they all want to conform to the same ul standards right?
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Single phase testing of multi-pole breakers is part of the UL489 standard test procedure. All UL489 Listed breakers are listed for this application.
 
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