Continuity

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electricalist

electricalist

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dallas tx
Checking out a 120/240 3 ph panel.
Tester on continuity from neutral to isolated ground bus. Both buses have the assumed correct conducters from dist panel.
Instead of a tone on my tester it was a hideous buzz.

Thanks to the Forum
 
electricalist said:
Checking out a 120/240 3 ph panel.
Tester on continuity from neutral to isolated ground bus. Both buses have the assumed correct conducters from dist panel.
Instead of a tone on my tester it was a hideous buzz.

Thanks to the Forum
Click to expand...

You have a 3 phase Panel 240/120 Delta Distribution with an IG Ground.

Continuity should be no different than in a regular panel.

Test the tester, then check your method, finally look into the issue if one and two check out.
 
Was your tester one of those automatic voltage/continuity testers?

The buzz was probably indicating voltage but low enough it didn't register any value the device can indicate.

This voltage may be either capacitive coupling, or even just the voltage drop across the neutral conductor if it is loaded.

Maybe measure voltage with a low impedance digital meter instead of a voltage/continuity tester and you will see any actual voltage present.
 
If found when it buzzez that voltage is present.
My concern is , it shouldnt have, unless theres a bad bond. Ill try the ohms

Thanks to the Forum
 
electricalist said:
If found when it buzzez that voltage is present.
My concern is , it shouldnt have, unless theres a bad bond. Ill try the ohms

Thanks to the Forum
Click to expand...

If there is load on the neutral there is a voltage drop across it. How much depends on the size and length, type of conductor, how much load, and (to lesser degree most cases) temperature.
 
electricalist said:
125 amp mlo sub panel 6 amp load. Some temped lights. 100' away partly cloudy.

Thanks to the Forum
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Another potential issue is what kind of lights? Those that produce harmonic distortion (like LED's or CFL) can produce more effects like you see then a linear type of load.
 
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