DSandstrom
New member
I build a small control panel for a client that attaches them to a larger system then ships them around the world. I used to localize each panel, but my client has asked that I create a standard panel that can be used anywhere. The design is pretty straightforward, everything in the panel is powered by 24VDC, there is a single 24VDC power supply that provides the DC power.
In the new design we have settled on a power supply that accepts 83-283 VAC, 50 or 60 Hz. That covers about 95% of the world. In addition, we've standardized on a two-pole, common trip, branch rated circuit breaker that is UL, UR, CE, TUV listed and 600V rated. The plan would be that in the US the panel can be used on 120, 240, and 277 V circuits, in Europe it can easily be used on 230 V circuits, and in Japan it can be used on 100 V circuits at both 50 and 60 Hz.
In the US we don't normally break the neutral with the circuit breaker, while in Europe and Japan this is standard practice. And it is allowed by the exception to 404.2(B) since we use a common trip breaker. We've had a couple of discussions with AHJ's about this, but once we point out the exception they generally see the light and now have a label mounted on the panel that points this out.
All of the background leads to the real question. What color wires to run between the breaker and the input to the power supply? In the US this would normally be black and white at 120, black and red at 240, then some color and white at 277. In Europe colors are all over, but the harmonized standard of brown and light blue must be accepted in new equipment. Japan also has different color standards, but will accept the European harmonized standard.
Which leaves me with the good old US. The one item I've been busted on a couple of times now is not having a white wire for the neutral at 120V. It's only a 6" long piece of wire, easy to replace, but it can cause a hassle that we'd like to avoid. My preference would be to settle on using brown and light blue. Worst case I could always ship extra "wiring harnesses" in the panel with instructions on changing them out, but that's a last ditch solution. What I'd prefer it to be able to add a label identifying a section of the NEC that allows alternate colors for these wires. So far I haven't found it. Anyone out there know of such a clause?
Thanks for wading through all that, any thoughts greatly appreciated.
In the new design we have settled on a power supply that accepts 83-283 VAC, 50 or 60 Hz. That covers about 95% of the world. In addition, we've standardized on a two-pole, common trip, branch rated circuit breaker that is UL, UR, CE, TUV listed and 600V rated. The plan would be that in the US the panel can be used on 120, 240, and 277 V circuits, in Europe it can easily be used on 230 V circuits, and in Japan it can be used on 100 V circuits at both 50 and 60 Hz.
In the US we don't normally break the neutral with the circuit breaker, while in Europe and Japan this is standard practice. And it is allowed by the exception to 404.2(B) since we use a common trip breaker. We've had a couple of discussions with AHJ's about this, but once we point out the exception they generally see the light and now have a label mounted on the panel that points this out.
All of the background leads to the real question. What color wires to run between the breaker and the input to the power supply? In the US this would normally be black and white at 120, black and red at 240, then some color and white at 277. In Europe colors are all over, but the harmonized standard of brown and light blue must be accepted in new equipment. Japan also has different color standards, but will accept the European harmonized standard.
Which leaves me with the good old US. The one item I've been busted on a couple of times now is not having a white wire for the neutral at 120V. It's only a 6" long piece of wire, easy to replace, but it can cause a hassle that we'd like to avoid. My preference would be to settle on using brown and light blue. Worst case I could always ship extra "wiring harnesses" in the panel with instructions on changing them out, but that's a last ditch solution. What I'd prefer it to be able to add a label identifying a section of the NEC that allows alternate colors for these wires. So far I haven't found it. Anyone out there know of such a clause?
Thanks for wading through all that, any thoughts greatly appreciated.
