Electric range safety ground

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Old 08-04-05, 09:26 PM
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Electric range safety ground

Iím redoing my kitchen and relocating the sink and dishwasher so Iíve removed the lower 2 feet of wallboard on adjacent walls to access the plumbing. Behind my electric range I found a non-insulated wire about 3/16ths-1/4 inch diameter which I determined to run from the main breaker panel ground buss to the copper pipe in the basement going to the water heater.

The electric range requires 240vac and 120vac and can be wired as a three or four conductor device. It is served by a # 6 (Al) three-wire cable with the neutral also used as a safety ground. I like to change it to a 4 wire connection by picking the ground off the water heater bare grounding wire and disconnecting the neutral wire from the rangeís grounding screw per mfgís installation manual. I would not cut the bare grounding wire, but use a mechanical screw connector. Is that okay per code? If OK, how would I insulate the bare, stranded neutral conductor?
 
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Old 08-04-05, 09:34 PM
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No you may not just pick up the ground from any point in the system.

You should run a new 3 conductor cable of the proper size, (Blk, red, white and bare ground) from the panel to the range location.
 
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Old 08-05-05, 05:31 AM
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Something does not sound right to me about your description.

Your main panel should be connected to the water pipes. If the pipes are the primary grounding means, then the connection should be near where the water pipes enter the house, not near the water heater. This makes me think that the water pipes are not your primary ground.

Anyway, there are certain instances where the ground for a circuit can be wired back to the water pipes. However, because of your description, this does not sound like one of them.

Run a new FOUR wire cable from the panel to the range.
 
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Old 08-05-05, 11:47 PM
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Originally Posted by racraft
Something does not sound right to me about your description.

Your main panel should be connected to the water pipes. If the pipes are the primary grounding means, then the connection should be near where the water pipes enter the house, not near the water heater. This makes me think that the water pipes are not your primary ground.

Anyway, there are certain instances where the ground for a circuit can be wired back to the water pipes. However, because of your description, this does not sound like one of them.

Run a new FOUR wire cable from the panel to the range.
I have a well with the water supply pumped to the house via a semi-flexible black plastic pipe . Waste water is via PVC. The electric meter is on a garage outside wall and the breaker panel is behind it on the inside wall. There's a thick bare wire from the meter going to the ground and also two other green insulated wires going to the telephone box and to the TV cable connector. The electric, cable, and telephone services are all underground.


...
 
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Old 08-06-05, 06:43 AM
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You cannot connect your range to the pipes no matter what.

For safety, your panel should be connected to your water interior metal pipes, but this is for safety, not for a ground.

You should ASAP have a proper ground installed for your electric, cable and telephone. This will probably consist of two ground rods driven into the ground.
 
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Old 08-06-05, 11:17 AM
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The single un-insulated wire apparantly is a "Bonding-jumper" between the interior metallic water-line and the Grounding Electrode system.

The frames of dryers and cooking-applianes are permitted to be Grounded to the Neutral (Grounded) conductor of the Branch-Circuit if these requirements are satisfied---

The B-C is EXISTING--- the Neutral is #10 copper or #8 Au minimum --if the Neural is not insulated, the Wiring Method is Type SE cable extended from the Service-panel.
 
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Old 08-11-05, 12:38 PM
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Okay - I decided to run a new cable for the range, 3 conductors plus ground(ing) wire. The existing breaker is a two pole 50 amp device and presently feeds a 60 foot run of # 6 aluminum (stranded). I'll need to run 75 feet of cable because I have to route it a little differently. The voltage drop calculators (assuming 50 amps) indicate I need # 6 al or #8 copper. If I recall the range only draws about 40 amps. It's going to be a difficult pull so I wonder if the copper cable makes the pull easier? I'm pushing 70 yrs old, so the money is less important than the physical work in a very hot attic. The existing neutral wire is braided and whoever installed it split it into two parts and connected it to the neutral/grounding buss by using two holes. I think there is provision for mounting a larger screw terminal on the buss, would that be a better method? Lastly the range can be hard wired per installation instructions if desired. I would use a flexible metal armored cable so the range can be pulled out for cleaning. There is access to the wall by removing the lower drawer of the range. I think hard wired is better, yes/no?

Thanks
 
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Old 08-11-05, 02:19 PM
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If you keep the 50A breaker, use at least #6 copper or #4 aluminum. Depending on the exact requirements of the range, you may be able to reduce to a 40A breaker and use #8 copper or #6 aluminum. All but the biggest ranges use 40A or less, so you would likely be safe with a 40A breaker and #8 copper wire. This will also be the easiest to install as #8 is the most flexible of the wire options; plus copper is more compatible with connection terminals than aluminum. Unless your range needs 50A, you should drop to a 40A breaker and use an 8/3 with ground type NM-B copper cable -- i.e. big romex with all conductors in the cable assembly.

I prefer cord-and-plug for ranges, but hard-wire is your choice. In all likelyhood, the range will be moved so infrequently that the extra work to disconnect a hard-wired connection is probably unimportant.

Yes, they do make bigger lug posts for larger cables -- check an electrical supply shop and they will have one to fit your panel.

Early morning is the best time to work in the attic if possible. Good luck!
 
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