Electrical Wiring in the Home/Wire guage recommendation


This will be a new 220v addition to my garage.  The ham radio amplifier will draw 10 amps each leg for 220 svc.  The run from the main is approx 80ft to the garage and may have to be run outside to get to the garage.  I cannot afford to experience any appreciable voltage drop to the amp. as it could affect the tubes and they cost $1500 each, as the amp costs $8000.

What gauge wire should I run? Will 10/3 work or do you suggest 8?

Past Navy Electrician...46 yrs ago.

Formula is Vd=K I L/ CSA
Where K is material factor value
         I is current
         L is circuit length round trip
         CSA is conductor cross section in circular mild
         Vd is voltage drop

Copper K value is 12.9
If you allow a 2 per cent voltage drop - 5 volts, you could use 14 gauge.
Ten gauge would give 1 per cent Vd
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Electrical Wiring in the Home

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Robert Wilber


Licensed Philadelphia electrician serving Delaware, Chester, Montgomery and Philadelphia County in Pennsylvania. I install and repair residential, commercial and industrial wiring and lighting. Troubleshooting and repair of problems that stump other people is my favorite. I am willing to help people figure out why things don`t work. I understand motor controls, transformers and machine wiring. I do not teach basics to novices or do free design work.


Experience in the area I have 44 years experience in residential, commercial and industrial electrical construction and repair, 480 volts and below. This is not to be confused with one week repeated two thousand times.

44 years experience in residential, commercial and industrial electrical construction and repair

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