Dave, If you have two ungrounded conductors and a grounding conductor then you can use the neutral bar as long as it is bonded to the panel. The neutral bar will no longer be a neutral bar but an equipment grounding bar. There is nowhere in the code that requires a neutral (grounded conductor) to be present in a panel past the main service. Just label the panel 240 volts Only- No neutral present to ease your mind. I have seen an ec add a 120v circuit from a panel with no neutral. Labelling it will prevent this problem.
Yeah ,.. and the O.P. has long since left the discussion .
I guess what I am saying is that I thought this slash rating issue was more of an issue when using a high leg.
I personally don't see a problem with doing the way the OP suggests.
If that 3rd. (grounded) conductor was insulated, I would strip the insulation from it and change it to a grounding conductor, install the bonding screw, and call it done.
If someone makes the mistake of adding 120V circuits to that panel, they shouldn't be doing the work in the first place.
If there's no white (or gray) wire in the panel, there's no way a qualified electrician would do it.
Just my opinion
steve
While this is most common with high-leg 240/120 3Ph 4W systems is it also a problem with ungrounded and corner/phase grounded systems.
If electrical work is being performed, and it is not by a professional who understands that it takes more effort than just doing, such as using one's experience and knowledge, then so be it. The mistake is theirs and the person who hired them.
When we go to work and have to worry about "what ifs", we might as well not go to work.
This thread is also an example of how hard it sometimes is to provide information when we do not really know the conditions of the installation.
Oh, to be able to lead such a sheltered life....99.9% of the systems I work with are Wye.
I stupidly ran a new 40 amp feeder for a HVAC circuit to a mostly empty 225 amp panel. I did not bother to open it up first, when I did open it I found the entire panel was supplied by 10 AWG and a very small transformer. Totally my fault, it did not even cross my mind that that the original installer should have labeled the panel as 30 amps
When we go to work and have to worry about "what ifs", we might as well not go to work.
Or in some cases to those who think you are staying from the topic :smile:
I thought the links you added were both relevant and informative. Thanks
There are always "what ifs" in the trade and no one is saying I have to wire for the "what if" situation. I just think that it would be a good idea to label the panel-- I never said it was required. It can't hurt and it doesn't take much effort.