Electrical questions

[Big Al]

I'm fixing up a late 40's house. I found some interesting wiring and I need some advice. From the box outside under the meter there are two conduits leaving. One has four wires all hooked to the neutral, the other has four wires all hooked to various fused "hots." Is this normal? I was expecting the hot and neutral in the same conduit?? I'm going to try to get a ground in the house at least for the kitchen and bath. I'm assuming these wires all go into the fuse box in the house. But then why would there be fuses in both places? There are no other wires going into the house from the meter area.

On a different topic. It also has a three phase circuit for the small shop. All three legs read 240 volts. If I was going to add some 240 volt machine, is it necessary that I use the phase that the 120 volt neutral comes from? Or can I use a different phase to balance the loads? BTW: The third leg reads 210 volts to neutral.

Al

[Speedy Jim]

Quite unusual to see that kind of service to residential property. Nonetheless, it's called a High-Leg Delta 3 ph service. As you noted, one leg reads higher to neutral than the others.

6

It's a simple way for the utility to provide *both* single phase 120/240V for lighting and also 240V 3 ph for machinery.

It's improper not to run the neutrals in the same raceway with the Hot conductors. Is it a huge deal in this case? Probably not.

The fuses outside are Main or Feeder fuses serving Branch ckt fuses inside.

Jim

[Pete C.]

Sounds funky, assume nothing, trace everything.

Three phase delta configuration with "wild leg". Loads that are 240V only i.e. have no neutral connection can be placed across any of the phases as you have 240V phase-phase in any of the combinations. Loads that require a neutral must be fed from the phases that have the neutral center tap. The "wild leg" i.e. the third leg that is 208V or so relative to the neutral must be marked orange and has other restrictions per code. There was a big discussion of three phase power options (Wye / Delta) late last year on rec.crafts.metalworking that you might be able to lookup.

Pete C.

[Bob Vaughan]

This is a code violation, and should be fixed. This wiring configuration can cause inductive heating of metal conduit, which could be a fire hazard depending on the load.

All phase and neutral wires of a given circuit must run thru the same conduit.