What is the working space reqd for 208vac panel?

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well maybe my question is what is the voltage of 208v nomial to ground - that's always confused me - i would guess it's in the 151-600v range - but somebody told me that b/c each leg has a max potential of 120v to ground then that falls in the 0-150 range.
there also something in the handbook that says a 208Y/120 volt 3 phase 4 wire is in the 0-150v.
i'm not an EE if you can tell
 
alexchilton said:
actually - i'm not 100% - what is a typicla 208V Flourescent lighting panel?
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The typical 208 panel will be 120 volts from any of the phases to ground and 208 between phases
 
alexchilton said:
i'm not an EE if you can tell
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You don't have to be. You just have to be able to draw a sketch.

Take a ruler and protractor. Draw 3 lines, 1.20 units long with a 120 degree separation in the shape of a "Y" (or evenly spaced). The ground is at the middle of the "Y", the lines are at the ends. You will measure 1.20 units to ground, 2.08 units line to line.

The same with delta. Draw a triangle with legs 2.40 units long. The ground on a high-leg system is in the middle of one of the legs, and the lines are at the corners. You will measure 1.20 units to ground on two of the lines, and 2.08 units to ground on the high-leg, and 2.40 units line-line.

The same will work for other voltages.
 
thx
i still don't understand why the working space isn't the higher of the two if you can get a 208v shock - or is the assumption that you will only touch one leg at a time or something?
 
alexchilton said:
thx
i still don't understand why the working space isn't the higher of the two if you can get a 208v shock - or is the assumption that you will only touch one leg at a time or something?
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Because there is no way to get a line to line shock from the wall.

If your back is contacting a grounded wall you will only be getting the line to ground shock.

You almost have to try to get a line to line shock. I once jammed the palm of my hand very hard against the bus stabs of a three phase 208 panel.

I basically crossed all three phases, not a recommended stunt, it hurt a lot.
 
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