All,
Local codes while important, are generally subservient to the NEC
(National Electric Code). This is put out by the insurance people and
failing to meet their requirements besides being un-safe could possibly
mean a denied claim. As a basic aside they are also the folks who rate
your fire department which sets the insurance rates. In almost all
cases local codes are based completely on the NEC
When the power comes into a standard house it has been derived from one
leg of a three phase 7(or so)KV distribution line each leg of which is
referenced to ground. This is why the transformer has only one wire
hooked to it's primary, the other side of the primary is tied to ground
at the pole. The secondary of this transformer provides 208 VAC with a
center tap (commonly called 208 split-phase). The voltage from either
side to the center is our normal 115. There is a ground bond made at
the transformer which ties the center solidly to zero volts.
Dave, If I read your mail correctly and you have 4 wires coming in from
the pole, you really need to check and make sure you have a ground rod
(or cold water pipe ground) bonded to the neutral bar at your service
panel on the house. Code requires that at service entrance there is a
ground to neutral bond. I have seen many locations without this ground
and electrical stuff blows up very nicely. This is also one of the
things that cause the lights to dim one place and get brighter somewhere
else as you turn stuff on/off. You may see this ground-neutral bond as
a bare copper wire screwed to the service box. The neutral bar will
have a tab or jumper that is bonded to the box. If there is a separate
ground bus it will undoubtedly also have a tab or jumper to the box.
In your case unless the units require 115 for something you only need
supply the 208 and a ground. The style of plug is important here.
There are several different spade (or twist-lock) plugs each supporting
a different voltage-current combination. This is to prevent plugging a
230V-30A device into 230V-20A service. So make sure you have the proper
socket and service for the device
Steve
__snip___
Dave in some states you are requiered to use a four wire connect because
the neutral and ground bus are isolated from each other and in most
older setups the ground bar and neutral are tied together so it's going
to depend on local code
___snip___
I am now ready to wire the new service for the new Hobart 230 VAC mig
welder and the new two stage compressor (for LBC work of course) in the
garage
There are three connections to wire the 230V plug, a rather large
vertical spade, a smaller vertical spade, and the usual U shaped lower
middle connector. The plug looks like a very large 115V grounded plug
(if you have seen a typical welding plug you know what I am talking
about) but my question since there are actually four wires servicing the
house ( 115V, 115V, neutral, and ground) is in reference to the
ground/neutral and are the connections as follows: 115V to large
spade. Other 115V to smaller spade. Now, to the actual question, is
the U shaped connector connected to
the ground or the neutral bar?
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