Residential code voltage

I'm just wondering if there is a residential code voltage maximum in the USA for residential properties. I have heard it differs from state to state. Up here in the great White North we have somewhat of a new rule that a "residential property cannot have more than 150 V to ground, distributed". A little bit of a game changer for us with our 600 V Machines.

That is pretty much it. There is also a 300V to ground level.

No problem INSIDE EQUIPMENT.... Old type TVs had 25,000 or more volts. So what exists inside is no issue. Branch circuits are what is limited.

Or NEON transformer in nearly every mom/pop bar not so long ago

JST said:

That is pretty much it. There is also a 300V to ground level.

No problem INSIDE EQUIPMENT.... Old type TVs had 25,000 or more volts. So what exists inside is no issue. Branch circuits are what is limited.

Click to expand...

Not clear on what you were looking for, but does this help?


Here is the link for a larger image:
http://machineryequipmentonline.com...t/uploads/2015/11/Voltage-Regulation-0755.jpg

In that ANSI chart, "Utilization Voltage" is what the equipment mfrs built to, i.e. motor design voltage, "Service Voltage" is what the utilities supply as measured at the Service Entrance terminals. The Service Voltage is higher because it is expected that there will be some voltage drop by the time you connect the motor / load terminals.

In the states, the code doesn't directly control the limit, which is up to your local power utility and public "agency having jurisdiction". In fact, the (latest revision of) National Electric Code is not universally adopted in all all jurisdictions. However, the code does restrict wiring methods at higher voltages (600V and above in particular calls for specific details).

It would be truly exceptional for a US residence to have anything but a 240V nominal three-wire, single-phase service. There simply isn't any residential equipment which requires a higher supply voltage. Some really archaic installations might be 120V nominal. The only other exceptions I can think of would be very high-end residences where the architect specified large commercial HVAC or kitchen equipment requiring higher voltage supplies.

While essentially nobody has a higher voltage supply, there is no blanket prohibition on higher voltages in residential settings. If I had requested a 480V service for my shop, located on a residential property, there would have been no code issue.

The manual I have from Ameren, the local utility, states that they Will. Not. Install. 3phase at a residence. Done, over with, no discussion.

No idea what they do with the mega-mansions that really should have 208 3 phase service. Everyone and his dog seems to live in huge houses here. I expect they DO install it.