DIYbanter - View Single Post - Can I plug my 230V compressor (NEMA 6-20P) into a dryer (NEMA 10-30R) receptacle?

(Martin Mickston) wrote in message . com...

What I *thought* was four breakers wired together, *appears* to actually
be two sets of two breakers (one I can read is labelled "TYPE BRD,
2 pole unit J1076, BR3030").

It appears that one set of two breakers handles the dryer circuit.
The other set of two breakers appears to handle the outdoor A/C unit.
All four are wired together with a copper wire through the handles.

Why would they be wired together?

Here's my best guess at what you got. Originally, there was a single
"2-pole" "common-trip" 30A breaker to run the dryer. This occupied 2
"slots" in the panel and carried the 2 hot legs to the dryer. Comes
time to add the A/C, there are no more slot pairs to add another
2-pole breaker. So the installer (probably the A/C guy) replaced the
2-pole with a pair of BR3030 "twin-pole" breakers. A twin-pole breaker
is like two half width breakers in the same package which can supply
two 120V branch circuits from a single hot bus in the panel. So, the
side-by-side pair of twins can supply two 240V circuits by considering
them as 4 poles with "inner" and "outer" pairs (poles 1-4 and 2-3) or
"over-under" (poles 1-3 and 2-4). The problem is, when one branch of a
240 circuit overloads and trips the breaker, it's supposed to trip the
other branch so that no part of the circuit is left live. That is why
common-trip breakers exist. The side-by-side twins were not originally
installed to do that, hence the home inspector flagged it. I've seen
worse combos.

Your situation is STILL potentially dangerous. A copper wire threaded
through the breaker handles is not the way to make a group of single
breakers into common-trip. Furthermore, one half of a twin-pole
breaker may not have sufficient strength to trip all 4 breakers hooked
together. The breaker manufacture sells appropriate hardware for
converting independent trip breakers to common-trip, and it is not a
piece of copper wire. If the hardware does not exist to fit that
particular combination, that combination is not meant to be hooked
together. Plus I don't think the BR3030 are listed for HACR service.
Your situation is almost certainly an "off label prescription" that is
not UL approved. Consider yourself so informed.

If you haven't had experience with working in a panel, you might not
want to start now. So the following merely tells some options. It's up
to you to make sure that it's up to code in your area and that it's
being done by qualified personnel.

Free up some slots in your panel by replacing some single breakers
with twin-poles for some 120V circuits. Depending on your needs for 15
or 20 amp branches, these would be Cutler-Hammer BR1515, BR1520,
BR2015 or BR2020 "replacement" breakers or BD1515, BD1520, BD2015 or
BD2020 CTL-tabbed breakers for notched bus stabs. This will leave you
enough space to install the PROPER separate 2-pole breakers for your
dryer and A/C, which would be breaker # BR230 in each case.

Another option is to replace the "homemade quad" with a real quad
breaker that's made specifically for this purpose. Cutler-Hammer makes
a model BRDC230230 which has inner and outer pairs hooked together to
make the equivalent of two 2-pole 230V breakers, but they also have a
less expensive BQC230230 for the notched bus panel if that's what you
have. No, you can't modify the cheaper one to fit the un-notched
busses.

See this for pictures:
http://www.eatonelectrical.com/unsec...B00300001E.PDF

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