blainebenson
Member
I have an installation by a computer/telephone supplier where a UPS supplies a 30A two pole panelboad.
The UPS is supplied by a 208V single phase circuit. The UPS then feeds a 5 kVA autotransformer (buck/boost) which then supplies the panelboard. The panelboard supplies six 20 A single pole circuit breakers to feed receptacles to supply power to various computer equipment.
Is a UPS considered a separately derived system? If so, how is to be grounded/bonded?
The issue I have is the paneboard has only one terminal bar in it and both the neutrals and equipment grounding conductors are all interconnected.
I think this is a violation of the NEC and the neutrals and grounds should be on separate terminal bars like a subpanel.
The vendor says this is how they install all of their panels fed from a UPS.
Is having the neturals and grounds interconnected at the panel acceptable? If not what is the NEC reference - is it 250.24 (A) (5)?
The UPS is supplied by a 208V single phase circuit. The UPS then feeds a 5 kVA autotransformer (buck/boost) which then supplies the panelboard. The panelboard supplies six 20 A single pole circuit breakers to feed receptacles to supply power to various computer equipment.
Is a UPS considered a separately derived system? If so, how is to be grounded/bonded?
The issue I have is the paneboard has only one terminal bar in it and both the neutrals and equipment grounding conductors are all interconnected.
I think this is a violation of the NEC and the neutrals and grounds should be on separate terminal bars like a subpanel.
The vendor says this is how they install all of their panels fed from a UPS.
Is having the neturals and grounds interconnected at the panel acceptable? If not what is the NEC reference - is it 250.24 (A) (5)?
