|[AMRadio] 220 volt AC Power Question|
lhwill at verizon.net
Mon Oct 30 21:08:43 EST 2006
John is correct. See NEC 250.138 and 250.140. It was common in old
equipment (my Heath SB220 is a good example) to have the control
circuits (PTT Relay) use the grounding (green) conductor for a
return. No longer permitted.
4 conductor plug/receptacle required. The green wire (grounding
conductor) is just that - grounding. Referencing the dryer example,
for old dryers, NEC says you must disconnect the bonding between
neutral (the 120V stuff) and the cabinet grounding conductor within
the dryer even with the 4 prong plug.
Basically the green wire is only a safety ground. There should never
be any circuit current flowing through that conductor.
Hope that helps.
At 08:50 PM 10/30/2006, you wrote:
>I understand that the update to the National Electrical Code now dictates
>that all NEW work 220V outlets have a neutral in addition to the ground. This
>makes good sense, especially in light of your email. Buy the way,
>legal or not,
>The Collins 30S-1 amp had an internal 120V outlet under a shelf in the power
>supply. This was to facilitate installing the power supply for a
>the amplifier PS cabinet. I don't doubt that other manufacturers and
>homebrewers do similar things with blowers, relays and control
>circuits. Dangerous? I
>suppose under the right circumstances it could be. For once, I can go along
>with the NEC folks.
>73 and stay safe,
>AMRadio mailing list
>List Home: http://mailman.qth.net/mailman/listinfo/amradio
>Partner Website: http://www.amfone.net
>Post: mailto:AMRadio at mailman.qth.net
More information about the AMRadio mailing list
This page last updated 23 Oct 2017.