Panel board

[Szavala]

Have to install one panel board, 3phase Delta,120/240volts, 84 circuit breakers is how was specs on plans, the maximum high of the circuit breaker according with NEC is 6' 7", is any other exclusion on the code that can install the panelboard that the highest breaker get higher that 6' 7"?

 

[hurk27]

Have to install one panel board, 3phase Delta,120/240volts, 84 circuit breakers is how was specs on plans, the maximum high of the circuit breaker according with NEC is 6' 7", is any other exclusion on the code that can install the panelboard that the highest breaker get higher that 6' 7"?

240.24(A) is very clear and the 4 exceptions would not fit your installation

could you install two 42 space panels? they would meet what you would need.

Also I would check with your utility to see if you can even get a 4-wire high leg delta, if so then use a single phase panel for all your 120 volt loads connected to A&C phase's as you can not put a 120 volt load on the B phase any way since it is 208 volts to the neutral on a high leg delta, then just install a 3-phase panel for just the 3-phase loads, also remember that the high leg is landed on C in the meter then rotated to B in the panel, and also it has to be marked orange

In the meter you will have A-B-C but in the panel using the same conductors you will have B-C-A with the C being the high leg orange wire or marked orange, doing it this way will keep the utility rotation the same which should be CCW which is the standard in most places.

I would do a RFI to the engineer to see if the print can be changed or if the utility doesn't offer a 4-wire delta then it will have to be changed.

Here our utility will no longer allow them as they tend to be one of the most unbalanced services because of the fact the B phase can't be used for 120 volt loads.

 

[hbendillo]

So I assume the engineer is just specifying the panelboard but didn't give you a panelboard schedule. I very seldom encounter Delta services anymore but we use double-section panelboards all of the time for 120/208 loads on a conventional system either bussed together or with feed through lugs. These panelboards would be side-by-side panels with circuits numbered 1-42 in Section One and 43-84 in Section Two. I suppose you could do that in your case too. I don't think you should mix three-phase and single-phase loads on a delta system. I think I remember special panels for delta systems that would have a top half where only three-pole breakers could be installed and a bottom half with the high-leg blanked off. The best practice is to use single-phase panels with no high leg for single phase circuits and three-phase only panels for three-phase circuits.

 

[GoldDigger]

Have to install one panel board, 3phase Delta,120/240volts, 84 circuit breakers is how was specs on plans, the maximum high of the circuit breaker according with NEC is 6' 7", is any other exclusion on the code that can install the panelboard that the highest breaker get higher that 6' 7"?

If the bottom of the panel is as close to the floor as its mounting arrangements allow and the top breaker is still too high, then you probably have no way around it. If you can create a permanent raised platform in front of the panel which is large enough to provide the required working space, you may be able to measure the height from there rather than from the original floor, assuming that you do not also have to worry about ADA issues, of course.