NEMA 10-30P to NEMA 6-30R adapter cable

Discussion in 'The Projects Forum' started by OhmBoy, Oct 21, 2013.

  1. OhmBoy

    Thread Starter New Member

    Jul 16, 2013
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    Hey all, I'm wanting to make a adapter drop cord to power a 240v/4800watt/20amp (NEMA 6-30P)-garage heater from my clothes dryer outlet (NEMA 10-30). I believe the dryer is 30amp at least, correct ? I'll be using 10 gauge wire.
    Any suggestions or comments before I attempt this ?
     
    Last edited: Oct 21, 2013
  2. #12

    Expert

    Nov 30, 2010
    16,248
    6,745
    Don't touch the electricity with your fingers, it bites?:eek:

    Really, you seem to have a good grip on this...
    Oh darn, a pun:(

    Go ahead. Nothing wrong that I can see.
     
  3. OhmBoy

    Thread Starter New Member

    Jul 16, 2013
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    I've just never done anything like this before so I'm a little scared. I'm renting this house so I don't want to have a outlet installed or burn down the place for that matter.
    Thanks for the vote of confidence.
     
  4. OhmBoy

    Thread Starter New Member

    Jul 16, 2013
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    Ok, this Electrician dude said to hook the Neutral from the 3 prong 10-30 (supply/old house) to my receptacle box/ground then loop it into the 6-30 Ground terminal. This is a drop cord not a mounted box so, Is that correct ? I thought Neutral can carry current coming from a old 3 prong 10-30 outlet. I'm scared that might be a shock hazard. I was thinking the Neutral and Ground should simply be wired straight across. I don't know so I would like someone to chime in before I burn the house down.
     
    Last edited: Oct 22, 2013
  5. #12

    Expert

    Nov 30, 2010
    16,248
    6,745
    Legally, the third wire does not carry current.

    Just use the connectors the way you expect to use them. Neutral to the neutral, and the hots to the hots. 3 wires running side by side, each one with one screw at each end.

    If that isn't the answer you wanted, slow down the next time you type. You're getting kinda jumbled...and tell me what country you live in.
     
  6. #12

    Expert

    Nov 30, 2010
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    6-30...small one. 2 horizontal and a bond pin
    10-30...big one. Crows foot. 2 angles and a bond pin.
    Does that clear it up?
     
  7. OhmBoy

    Thread Starter New Member

    Jul 16, 2013
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    Sorry about the jumbled up part. I'm in North Carolina/USA... I had been up working all night and now I'm just waking up. Third shift can make the mind wonder (HaHa).

    Anyway, before I came home and wrote my last statement I had that same electrician dude hook everything up the way described (his way). I plugged the heater in for about 30 seconds to one minute and everything worked. Its just I started thinking while the metal receptacle box was laying across the carpet that if for some reason it decided to ground out then my floor would become the current path (not good). That being said, am I right for thinking he must of thought this receptacle box was to be hard mounted ? What was his theory for applying this box ground in the first place, a code thing or something ? Doesn't the Dryer use the Neutral as ground just like the heaters 6-30 plug ?

    Thanks so much for your help :)
     
  8. #12

    Expert

    Nov 30, 2010
    16,248
    6,745
    How many wires are in the cable?

    If you want the neutral wire and the bond wire, wired straight across, straight across to where?

    If you want a neutral and a bond and 2 phases of 240 volts, you need 4 wires in the cable.

    If the electrician already connected the metal box to neutral, why would the box "ground out" to the concrete and what would that hurt?

    Yes, the electrical code says metal boxes must be connected to the bond wire.

    Do you have any knowledge that any appliance is using the neutral wire to carry current?
     
  9. OhmBoy

    Thread Starter New Member

    Jul 16, 2013
    8
    0
    You kind of confused me but I'll explain what I can.
    *My supply cable is a standard 3 wire 10-30P Dryer cord with 2 hot and 1 Neutral.
    *My receptacle side is a 6-30R as pictured above. It has 2 hot and 1 "Ground".
    *My receptacle box is metal with a build in bolt for a ground (which the electrician ran the 10-30P "Neutral" around then into the receptacles terminal.
    My confusion is why he routed the 10-30P Neutral to the metal box ground before actually inserting the wire into 6-30R inlet.

    Like I said, its working fine.
    I'm just concerned that in case of a fault the ground will find a path of less resistance out of the metal box ground instead back to the breaker box. That being said, should I leave it alone or take the metal box ground loose so that the ground/neutral are wired straight to the breaker box ?
     
  10. #12

    Expert

    Nov 30, 2010
    16,248
    6,745
    Leave it alone. The National Electrical Code says the metal box must be grounded. The metal boxes have suffered thousands of tests and developments to make sure the current can not find a path of less resistance with which to get out of the box.

    "In case of a fault, the ground will find a path of less resistance (than a copper wire) out of the metal box ground, instead back to the breaker box."

    In case of a fault, the ground doesn't find a path, the current finds a path. There is no path of less resistance than copper unless you have a lot of silver laying around that can accidentally get connected to electricity.

    The ground/neutral wire IS wired straight to the breaker box. Also connecting the metal outlet box does not disconnect the copper wire from the ground bus in the breaker box. Even if you use a few inches of ground wire to make a loop for the wire to be captured by a screw in the metal box, it will not interfere with the ground wire being connected to the ground bus in the circuit breaker box.
     
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