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Thread: shocking electric water heater
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05-07-2012, 10:24 PM #1
shocking electric water heater
I replaced an electric water heater today with gas so I went to disconnect the wiring at the timer they had installed. The power enters from the distribution panel on the left and exits to the heater on the right. Note the neutral wire was never connected to the WH. The water pipes completed the circuit. Oooh, baby!
Keep the fire inside the fireplace.
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05-07-2012, 10:36 PM #2
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Don't water heaters run on straight 240v? Neutral is only needed for 120.
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05-07-2012, 11:16 PM #3
clarification
I shouldn't have referred to it as the 'neutral' but in the case of 220/240 vac it serves as a grounding conductor which 'should' be connected here at the timer bonding. I also didn't clarify there was a loose hot wire inside the WH where it slipped out of the Marrette and was about to energize the WH. Normally, the pipes would complete a ground but it was broken by some PVC without a bonding jumper. The two hot wires are hot to the thermostat and swap phases once the stat closes on a call for more hot water. However, in this case, the loose hot wire inside the cabinet where the cable enters the WH would not be grounded by the two hot wires. Anything that gets electricity really should be bonded regardless IMHO.
Keep the fire inside the fireplace.
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05-07-2012, 11:25 PM #4
not anywhere close to your issue, but saw one today, there for the furnace, that they installed the ball valves onto the nipples at the water heater.
the funny thing is there is a union, water flex and nipples on both sides above the water heater, somebody was not thinking.If Guns Kill People, Do Pencils Misspell Words?
http://www.youtube.com/watch?feature...&v=2kX_3y3u5Uo
http://www.youtube.com/watch?v=JVAhr4hZDJE
http://www.youtube.com/watch?v=-TC2xTCb_GU
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05-08-2012, 12:26 AM #5
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05-08-2012, 05:14 AM #6
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05-22-2012, 07:50 PM #7
Yea, I've touched too many appliances and said.....whoa, sheet.....wtf?
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05-22-2012, 08:37 PM #8
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05-23-2012, 04:42 AM #9
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05-23-2012, 07:01 AM #10
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05-23-2012, 12:56 PM #11
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Well, looking at the picture I see BX cable, not MC so the armor serves as the ground. Hence the reason for no green wire in the cable and the presence of the bonding wire, meant to keep the armor from heating in the event of a ground fault. Now if the locknuts are not made up tight or the cable is not properly inserted onto the connector then the ground is compromised.
Also, if the motor in the timer is 120v, that would explain the need for the neutral on the feed. If the motor on the timer is in fact 120v then you cannot use the white wire as a ground as it is being used as the neutral for the timer motor. Basically, if you connected the white wires together in the timer and bonded the white at the water heater to use as a ground and the white wire was also connected to one side of the timer motor, then a fault in the white wire between the panel and the timer would make the water heater hot literally!
Using the latest codes if the system is metal pipe then there should be a bonding jumper across the heater piping. The reason for that is so that if the water system has a continuous ground regardless of whether the water heater is present, absent, plastic or metal.
With all that said I agree, I hate BX cable and agree that a ground should be a wire in the cable and not the sheath of the cable. But there are millions of BX installations going strong to this day.


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