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Author Topic: Need help with panel  (Read 850 times)

Doug Fowler

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Re: Need help with panel
« Reply #10 on: August 25, 2014, 02:08:09 pm »

All good, A and C phases got it done.

Later I found a PostIt note on the floor that read "DO NOT USE THE B PHASE".

Thanks everyone.
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Lee Buckalew

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Re: Need help with panel
« Reply #11 on: August 25, 2014, 03:26:40 pm »

All good, A and C phases got it done.

Later I found a PostIt note on the floor that read "DO NOT USE THE B PHASE".

Thanks everyone.

Post It's are the universally recognized safety standard for transmitting warning information.  :-)

Lee
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Lee Buckalew
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Cailen Waddell

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Re: Need help with panel
« Reply #12 on: August 27, 2014, 08:06:51 am »

So, a question about this situation I have been thinking about for a couple days. 

Are the hot legs still 120 degrees out of phase with eachother?  With where the neutral is derived and the phase relationship of the hot legs, are neutral currents on a 120v/240v split phase distro a concern?  Is my actual capacity lower so I don't overload my neutral?

Thanks for the consideration....


Sent from my iPhone using Tapatalk
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Mike Sokol

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Re: Need help with panel
« Reply #13 on: August 27, 2014, 11:18:02 am »

So, a question about this situation I have been thinking about for a couple days. 

Are the hot legs still 120 degrees out of phase with eachother?  With where the neutral is derived and the phase relationship of the hot legs, are neutral currents on a 120v/240v split phase distro a concern?  Is my actual capacity lower so I don't overload my neutral?

Thanks for the consideration....


Sent from my iPhone using Tapatalk

The 120-volt phases on a high-leg delta are actually at 180 degrees phase, forming what works and measured like a standard 120/240-volt feed. So its neutral current will be totally subtractive, just like any single-phase feed in the USA.

Just stay away from that "high-leg" since it's 208 volts from the neutral. Plus the POCO doesn't want any current drawn between the high-leg and neutral since that will cause all sorts of unbalancing to happen in the transformers.

Stephen Swaffer

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Re: Need help with panel
« Reply #14 on: August 27, 2014, 11:30:34 am »

The 2nd transformer will not affect the relationships on the split phase transformer. I have a customer with a an open delta-the POCO used a regular split phase transformer for that portion and just added a transformer for the wild leg.

Only 3 phase or phase to phase should use the wild leg-so they should not contribute to neutral currents.

If you use only the 240 volt split phase transformer to feed your gear, I see no significant issues.
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Steve Swaffer
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