[Amps] 3 or 4 wire 240v for amp

Vic Rosenthal vic at rakefet.com
Wed May 4 01:17:43 EDT 2005


RadioMB at aol.com wrote:

> Hello,
>   I have just moved to a new house in FL. I had a 240v line run to the ham 
> shack. The box contains 4 wires. The normal red and black hot wires, a copper 
> ground wire, and a fourth white wire. Is the white wire a neutral wire? Since my 
> Drake L-7 has 3 wire cord (two hot and the ground wire). Do I now use the 
> white neutral wire or the copper ground wire as the third wire in the line cord? 
> When adding the new plug to the three wires from the Drake do I just not use 
> the fourth wire? Does this meet code for a 4 wire system? Thanks for your 
> replies, looking forward to using the L-7 again.

The ground wire in the cord from the Drake should be checked to make sure it is 
actually grounded to the chassis.  This wire should go to the copper ground 
wire.  The white neutral is not used.

You would use the white wire if you needed a 120v circuit in addition to the 
240v.  In that case the line cord to the equipment would contain a neutral wire 
(which should NOT be connected to the chassis ground) in addition to the ground 
wire and the two hot wires, and you could get 120v between either of the hot 
wires and the neutral.

Someone familiar with the code can tell you if it is more correct to install a 
4-wire socket and plug (leaving the neutral terminal of the plug on the Drake 
unused), or install a 3-wire socket and plug (leaving the white wire unconnected).

-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco


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