3 wire versus 4 wire?

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CallMeVilla

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The debate is on! The existing 220VAC outlet , 3 wire (twist lock) does not conform to the 4 wire (straight blade) plug on the new equipment.

One guy says there is a pigtail adapter.
One guy says NO WAY !

I say we need to re-wire from 3 wire to 4 wire (same amps).

What say you?

RANGE-4-WIRE-OUTLET.JPG
 
The debate is on! The existing 220VAC outlet , 3 wire (twist lock) does not conform to the 4 wire (straight blade) plug on the new equipment.

One guy says there is a pigtail adapter.
One guy says NO WAY !

I say we need to re-wire from 3 wire to 4 wire (same amps).

What say you?

The first question that I have is which equipment are we discussing? That makes a lot of difference in some circumstances. If you chose the right picture your new equipment requires between forty to sixty amperes of 240/120 Volt single phase AC power. You cannot get that safely from a 220 volt single phase receptacle outlet because you would have operational current flowing on the Equipment Grounding Conductor (EGC). The voltage drop that will be caused by that current flow may raise the touch potential of exposed conductive surfaces above safe levels.

You will not find a pigtail adapter with a laboratory listing mark to make that conversion. If the circuit cannot be economically replaced then you can create a derived system to supply the needed voltage by installing a properly sized transformer at the load end of the circuit but those transformers are not cheap. It is usually more cost effective to rewire the existing circuit to include both an EGC and a Neutral conductor to a four wire receptacle outlet.

--
Tom Horne
 
Made the call based on new information ... Existing is 3 wire #10. The new equipment will be ..... wait for it .... a charging station for a Tesla all-electric car.

The specs call for a 4 wire, #6 to handle the load. The circuit will be pulled with new wires.

Yeah BUDDY !

TESLA.jpg
 
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