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.
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
It's a simple way for the utility to provide *both*
single phase 120/240V for lighting and also 240V 3 ph
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.
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.
-- Welcome My Son, Welcome To The Machine --
Bob Vaughan | techie @ tantivy.net |
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
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