I am in the process of installing a subpanel using a pre-existing 220 line that is not being used now, but was used for a water heater. The problem is, measuring accross the hot wire and ground I get a normal reading of 115. Measuring across the neutral and ground I get a reading of 94v. at the main panel, both lines read correctly, 110-115. The cable from the main to the subpanel is short, not more than 3 feet. Both boxes are the old edison type fuses and have been converted to s type. Any input would be appreciated. thanks. Randy
There is a difference between "Ground" and "Grounded".
The bare ground wire is for safety only, and not a return wire for the power.
The white wire is the return wire. It is called the "Grounded" wire, because for reference it is tied to the ground at the main panel. ONLY at the main panel, nowhere else! From there on down the line, the white and the bare are not common.
You need a white wire big enough to carry all the return current from the sub panel, connected between the silvery terminal strips in both panels. That is the most important wire and needs to be connected the best. If you see the slightest bit of corrosion or discoloring, trim it back to bright, shiny metal, or replace the cable.
The red and the black wires are the power wires. They go to normally brass colored bus bar terminals above the breakers or fuses, and continue from the brass colored screws on the breakers or fuses.
Once you have a good and solid connection from white to white (silvery) between the panels, you should get normal readings from black to white and red to white.
Personally, I would take those ancient panels out, clean them up, take nice pictures of them and flog them on e-bay. There are people who collect those!
With the money from that, I would buy some modern breaker panels that are built according to today's standards and codes. I would not trust any panel that is more than 25 years old. There could be cracks and corrosion in it that will sooner or later cause problems.
what size line should i use for 45 feet of 220 line.
To power a 220 Volt CD player in Europe you could get away with lightweight #16 lamp cord. To power a 50 Horse Power 220 Volt pump you would use AWG #2 cable. To power a detached workshop with various machines, power tools, welder, and an air compressor, I would also use #2 cable.
The voltage is irrelevant as far as copper thickness is concerned. voltage is only considered for insulation type and thickness.
What needs to be known is the maximum Amperage that runs through that cable. All electrical devices except light bulbs have their Amperage listed on them somewhere. Add all the Amp numbers together and then look up the wire size in the code book or at http://webby.com/techtips/ampacity.html
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