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I'm replacing a dryer that has a 3 prong receptacle. The receptacle has 2 hot wire connections and a ground wire hooked to the neutral. My new dryer has a grounding strap hooked to the neutral and to the body of the dryer. Do I need to disconnect the grounding strap since the ground is being used as the neutral?

The receptacle, with two hot wires and a ground as a neutral:

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The breaker is in the main box. Wired normally.

  • Can you show us how this is hooked up at the breaker panel end? (You'll have to turn the main breaker off and be very careful not to poke the line-lugs as they'll still be live, or have the power company cut the power for you temporarily, before pulling the deadfront off the panel) – ThreePhaseEel Sep 13 '17 at 1:03
  • Use the edit link underneath the post if you want to update it with new information, or the add a comment link if you want to reply to another user. – Niall C. Sep 13 '17 at 1:28
  • All the grounds are on the ground bar, and all the neutrals are on the neutral bar. The black and red wire come out of the breaker – Rick Harper Sep 13 '17 at 1:40
  • I take it it's the main panel, right? Can you trace the black and red from the dryer breaker to where they enter the cable jacket, and take a photo of that? – ThreePhaseEel Sep 13 '17 at 1:57
  • Not letting me send that pic, but 4 wires coming out of jacket – Rick Harper Sep 13 '17 at 2:08
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What you have is 2 hots and a ground being misused as a neutral. This is dangerous and illegal. It would also be dangerous and illegal to misuse a neutral as a ground, except that a special exception was made in the Code to make it legal here.

Usually when you see these obsolete/dangerous NEMA 10 receptacles, they are this way because obsolete wire was used, and wire is hard to replace. However, if you look closely, it is modern wire with both neutral and ground. Clearly, the house originally had the modern, safe NEMA 14 type receptacle, and somebody got a used dryer with an obsolete NEMA 10 cord, and fit the NEMA 10 receptacle instead of a NEMA 14 cord.

When the NEMA 10 fails, it fails deadly, electrifying the chassis of the machine. It has a track record of killing people, although some deny this - the problem is, these accidents are typically miscategorized as miswired outlets (botched wiring) when in fact the wiring was correct and simply failed.

For safety, I would put it back to the modern, safe NEMA 14-30 receptacle and cord. Either pull some slack from that 4-wire cable, or lower the receptacle 2 inches so you can get use of that neutral wire.

When you fit the NEMA 14 cord, remember to remove the ground-neutral link on the dryer. Neutral should go to power terminals, ground should go to chassis, and they shouldn't be linked.

  • Thank you! Oakwood mobile home had it wired like that. I'm going to rewire it correctly! – Rick Harper Sep 13 '17 at 16:03
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In answer to your question do not remove the ground from your appliance. The real question is does your dryer need a neutral? Look for the appliance nameplate it should say either 120/240V or 240V. The 120 indicates it is using a combination voltage and 120V needs a neutral. The 240V tells you it only needs a single voltage and does not need a neutral. Per NEC if it needs a neutral then you need to install a four prong receptacle and matching four prong appliance cord.

Hope this helps. Stay safe.

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