Water heater question

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I just installed a new 480 volt 3 phase water heater and get a reading of 3/10 amp on the EGC. The conduit is used for ground from the switchgear to the heater disco; green wire ground from disco to heater. Is this a bldg ground problem or is the problem with the water heater? Any advise would be appreciated.
 

mdshunk

Senior Member
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Right here.
I'm not so sure I'd worry very much about 3/10ths of an amp. By what means was this measured? What was the current draw on the phase conductors at the time?
 

iwire

Moderator
Staff member
Location
Massachusetts
Based on the limited info I have on this end I suggest this.

Shut the circuit off supplying the water heater, it is my bet you will still have current on the EGC.

It's most likely unbalanced neutral current circulating on the metal piping and EGC due to multiple bonds either inside or outside the building.

But not having looked at the installation myself that is a pretty big guess. :smile:
 

captaincrab55

Senior Member
Location
Maryland
iwire said:
Based on the limited info I have on this end I suggest this.

Shut the circuit off supplying the water heater, it is my bet you will still have current on the EGC.

It's most likely unbalanced neutral current circulating on the metal piping and EGC due to multiple bonds either inside or outside the building.

But not having looked at the installation myself that is a pretty big guess. :smile:
Sounds like the problem.... Remember that current will help to eat the tank away too!!!...
 

mdshunk

Senior Member
Location
Right here.
captaincrab55 said:
Sounds like the problem.... Remember that current will help to eat the tank away too!!!...
Guess you missed that MythBusters episode, where they tried to cut jail bars that way? ;) You really don't get that sort of action from AC.
 

quogueelectric

Senior Member
Location
new york
The current is probably from the service

The current is probably from the service

Running in parallel to the water pipes from the ground conductor attatched.
 
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