Ungrounded Electric Water Heater

Originally Posted By: jcooper2
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http://www.nachi.org/bbsystem/usrimages/d/dscf0020_edited.jpg ]


Originally Posted By: dandersen
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It sounds like the conduit is being used as the ground source.


If properly installed, the conduit can be used as the ground.


Originally Posted By: rmoore
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“There was no ground wire run within the conduit.”


As Dave said, metallic conduit can serve as the equipment grounding condutor as long as continuity is maintained. You'll also see this in taller condos where all wiring is run in conduit.

"Moreover, the copper piping connections are dielectric, so there is no metal to metal ground connection to the house plumbing. (as it should be)."

??? I'm not sure what you are getting at there. In your photo the hot/cold bonding jumper is properly installed above the flex hoses, so that the bond remains even if the water heater and flex is removed.

"Will a connection from the ground lug on the water heater to the grounded house plumbing be sufficient?"

No! Assuming you didn't have the conduit or a regular grounding wire, you cannot use the water piping as an EGC. Equipment grounding conductors are used in the case of a ground fault to reliably pass current to the utility's grounded conductor by means of the bond at the service equipment, and thereby trip the OCPD. Too many uncertanties in the water piping to rely on it for that purpose (even if it would work in most instances). EGCs have to be run with the current carrying conductors.

In other words, the water (gas, etc) piping is bonded to prevent shock if it is accidently energized, not to act as any equipment ground.

I think that is right. ![eusa_think.gif](upload://lNFeGuTetUAtwNVgUSOuUzgrGGK.gif)

Anyway...the set-up in your photo (and the way you describe it) looks good to go. That fabric or wallpaper in the photo could kill you though. That's some ugly crap!


--
Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com

Originally Posted By: jcooper2
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Thanks guys.


My doubt was enough for me to cause me to ask the question. I checked continuity for just that reason., i.e. to see if indeed the heater was grounded through the conduit. I have seen a green braided wire inside the conduit along with the two hots, and wasn't sure which was proper.

John


Originally Posted By: bbadger
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John as far as the NEC is concerned the steel conduit and or a coper grounding conductor is correct.



Bob Badger


Electrical Construction & Maintenance


Moderator at ECN