Plumber replaced an existing water heater that was fed by a 200amp fused 3 phase knife disconnect. New HWH was only a 3p50. So instead of change existing disconnect he tried to get 50 amp fuses but JJNL don't come in 50 amp fuses. Therefor he fed a 60amp rated disconnect with 50amp fuses from this 200 amp disconnect with 8awg from load side of this disonnect to line side this 60amp disconnect then fed the new HWH. Are there any black and white code issues with this? Thoughts and comments appriciated.
HWH 3phase Disconnect
- Thread starter Aledrell
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Distance and method
Distance and method
The 200 amp disconnect is about one foot away from the 60amp, feed with number 8 THHN through metal flex. The feed is broken here and then continues to HWH through a seperate metal flex. I agree that this sounds like a tap but unsure if this is considered safe. I think so, better than some installations I've seen.
Distance and method
The 200 amp disconnect is about one foot away from the 60amp, feed with number 8 THHN through metal flex. The feed is broken here and then continues to HWH through a seperate metal flex. I agree that this sounds like a tap but unsure if this is considered safe. I think so, better than some installations I've seen.
- Location
- Logan, Utah
As long as the conductors from the 200 amp disconnect to the 60 amp disconnect are not longer than 10 feet and meet all the other requirements of 240.21(B)(1) then you should be OK.
You would not be able to use the 25' tap rule of 240.21(B)(2) due to the fact that the #8 conductors have an ampacity than 1/3 of the 200 amp fuses.
Chris
You would not be able to use the 25' tap rule of 240.21(B)(2) due to the fact that the #8 conductors have an ampacity than 1/3 of the 200 amp fuses.
Chris
JohnJ0906
Senior Member
- Location
- Baltimore, MD
I think it meets the requirements of 240.21(B)(1), except I'm not sure this is actually a tap.
240.21(B) - "conductors shall be permitted to be tapped, without overcurrent protection at the tap, to a feeder as specified in 240.21(B)(1) through (B)(5)"
Does this count as being "tapped to a feeder"?
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
The 50A fuse is the last overcurrent protective device, so everything going to that fuse is a feeder and the circuit leaving that fuse is the branch.
JohnJ0906
Senior Member
- Location
- Baltimore, MD
Works for me. :smile:
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
What is a HWH? If its a Hot Water Heater, is it really needed?
Tom i think the feeder to the 200 amp fused disconnect protecting the hot water heater still has an OCPD in excess of article 422.11(A) or (E).
Rick
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