DIYbanter - View Single Post - GFCI Circuit protection question-outdoor wiring

wrote:
On Mon, 26 Sep 2005 19:30:30 GMT, HorneTD
wrote:

The higher voltages cannot be derived from the same circuit without
installing a transformer so the code language permits you to avoid that
bit of expense and complexity. The code language on which you are
relying is meant to allow separate circuits for such purposes as
powering a large item of equipment that requires a completely different
voltage such as 240 volt delta three phase with one phase grounded to
run a large refrigeration unit. You need the 240 / 3 phase power for
the refrigeration unit and you need 120 volt power for service
receptacles and lighting. Since 240 volt delta is much cheaper to
install as corner grounded delta the cost effective way to provide both
voltages is to run two circuits. Another example is a guard house for
an industrial complex that has 480/277 volt air conditioning and
lighting together with 208/120 volt power for receptacles. In short
those exceptions are only intended to be applied were a single branch
circuit or feeder cannot supply the needed power.

That is not what the code says. In fact the handbook shows a combo
NEMA 5-15 and 6-15 device in the example.
(a duplex receptacle with a 120 and a 240 outlet)

Now I understand what you are saying. The higher voltages I was
referring to are the ones that the OP was referring to such as 480/277.
Such higher voltages cannot be derived from the same circuit without
using a transformer as opposed to may not be derived from the same
circuit because the code prohibits it which it does not. My point was
that the exception allowing multiple feeders or branch circuits for
different voltage characteristics does not apply to situations were the
needed voltages can be derived from the same circuit. I do not see any
conflict between our two postings. I was urging the OP not to run two
circuits to obtain the 240 & 120 volt circuits he needs. I believe you
were suggesting that he use a single multi wire branch circuit to
accomplish that.
--
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous
for general use." Thomas Alva Edison