American voltage level

[68709359]

Hi All,
I am invloving one project which which employ american voltage level. As far as I know, american has the following voltage type(60Hz):
120/208V for lighting and outlet, solid earthed
240/416V for ? solid earthed
277/480V for LV such as motor, solid earthed
2425/4200V for MV load, low resistance earthed
the Higher voltage ?

Could anyguys help me to confirm whether it is right and detail it? what type of consumer will use which voltage?
In general, what's standard transformer type?

thanks in advance

 

[stevenal]

skogsgurra's story reminds me of a generator I saw at the Bonneville dam. On the side of this huge generator was a 15A 120V receptacle. Just seemed a little like overkill.

 

[rmw]

Think of the toaster that that would have run....

rmw

 

[jraef]

15A is 15A, but think of the fault current if the toaster shorted!

 

[davidbeach]

A 15A receptacle fed through a 45kVA (a guess) step down transformer really isn't going to have much more fault current behind it at Bonneville than it would much further down the power system.

 

[jraef]

... it was a joke.

 

[davidbeach]

So, where was the ;-)?

I figured you ought to know that, but who know about some of the readers that might stumble across that.

 

[ITSTOAST]

In my area a typical, modern, non-manufacturing facility would have a MV service at 13.2 KV this would be transformed at the main service to 480/277 volt 3phase 5 wire. This voltage is distributed to the electrical rooms where the panelboards supply the motors and large loads with 480 volt 3 ph. The panels also supply the 277 volt 1 ph.lighting loads with power that is derived from one leg of the 480 and the grounded neutral for the 277 volt.
At the main service the 13.2 KV also feeds a second transformer for the 208/120 loads such as the wall receptacles and other loads such as VAV boxes on the A/C system. All transformers are Delta primary/Wye secondary with the neutral grounded. Manufacturing facilities, old buildings, and residences use some of the other voltages and configurations mentioned elsewhere. Hope this helps.