>
>Hello Paul,
>
>I am an Electrical Engineer for a large Electrical contractor in Michigan.
>We don't do much Residential, but I think I can help you out. See comments
>interspersed below:
>
>>As I begin to add a 240VAC power drop to my radio shack at the new QTH, I
>>began to consider cable sizing, connectorization and grounding issues. At
>my >previous home, I used #10/3 CU cabling for a total distance of 60-feet
>to my >Alpha 77Dx (single tube). I then terminated the drop into a Hubbell
>30-amp >Twist-Lock receptacle. I then began thinking about various 240VAC
>distribution >possibilities:
>
>The 10/3 is fine if your circuit draws less than 30Amps.
10-3 is not fine for capacitor filter supplies that draw an indicated
30a. The problem is that peak current is 8 - 10 times higher than
indicated current. My advice is to use 10-8 or even 10 - 6 for long
runs.
>You should have 2
>lines (or phases as you have called them) and a grounding conductor.
agreed
>There
>is no neutral in this type of an installation.
The N is connected to ground at the circuit breaker panel.
>If you have a long run,
>voltage drop should be considered. I would be happy to calclate it for you
>if you provide the distance and load in ampres.
>
>>1) Some 240VAC circuits employ two phases and a ground, but no neutral.
>
>You will not need a neutral if there is not requirement for 120V. in this
>equipment (remember line-neutral = 120V)
>
..
>Be sure to use an equipment grounding conductor to keep the cabinet at
>ground potential.
>
Amen to that, Eric.
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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