110V from 220v pump circuit

DBachman

I am installing a 220v well pump, and have a 110V clorine injector that needs to run at the same time the pump is running.

I was thinkng of using a transformer to step down from 220v to 110v, but it would seem easier to run 4 wire cable for the 22OV, use the red and black for the 2 sides of the 220V (plus ground), and then connect to the black on the pressure switch to switch on the injector, while connecting the white neutral thu to the injector.

Apparently this is how some dryers run both 220v and 110v from a single 4 wire 220v line. I just wanted to be certain I wasn't overlooking anything. Somewhere I read that the breaker for the 220v will detect a difference in load between the 2- feed lines and thus be a problem.

Thanks,

kbsparky

Using a 4-wire circuit is the best procedure for this. Be sure to use a 2-pole breaker, and 2-pole disconnect switch at the pump house.

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DBachman

Doesn't a breaker for 220V have to be 2 pole anyway? what else would it be to get current for 2 live poles?

Pump pressure switches are 2 pole for the 220V pump, but it would only be the one side that I then attach thwe 110V injector.

rjniles

Some people have been known to use 2 single pole breakers to supply a 240 volt load. It will work but it is wrong.

__________________
Location:
Coastal South Carolina

Code05

Perfectly legal if the breakers have a handle tie between them.

240.15(2) Grounded Single-Phase Alternating-Current Circuits.
In grounded systems, individual single-pole circuit
breakers rated 120/240 volts ac, with identified handle ties,
shall be permitted as the protection for each ungrounded
conductor for line-to-line connected loads for single-phase
circuits.

rjniles

Some people have been known to use 2 single pole breakers to supply a 240 volt load without a handle tie or non-adjacent breakers. It will work but it is wrong.

Don't you think for the average DIYer on this forum it is better to say use a 2 pole breaker fro 240 volt circuits that get involved with handle ties?

__________________
Location:
Coastal South Carolina

Code05

Yeah, you are right. I will remember that.

Master of Cold

Are you guys sure this is legal?
I have had an inspector freak out after wiring in a condensate pump (120v) to the air handler power (240v), with a neutral back to the box. Got busted by 3 different inspectors doing this.
One of the inspectors said the wiring to the pump couldn't carry enough current to trip the 60amp breaker.

Code05

You got busted 'cause what you did was illegal.

We were talking about a multi-wire branch circuit. 20 amp 240v and 20 amp 120v mixed on a properly sized breaker and using properly sized wires.

Think of a dryer or range circuit.

micromind

The proper way to do this when the 240 circuit is larger than 20 amps is to install a fused disconnect switch to protect the smaller wiring.

It's done on a regular basis on commercial A/C units that have condensate pumps. It can even be done on a 208 or 240 volt 3 phase circuit. Just don't use the high leg if it's a 240 delta.

Code05

Dat works.

240.21(B)(2)

(2) Taps Not over 7.5 m (25 ft) Long. Where the length of
the tap conductors does not exceed 7.5 m (25 ft) and the tap
conductors comply with all the following:
(1) The ampacity of the tap conductors is not less than
one-third of the rating of the overcurrent device protecting
the feeder conductors.
(2) The tap conductors terminate in a single circuit breaker
or a single set of fuses that limit the load to the ampacity
of the tap conductors. This device shall be permitted
to supply any number of additional overcurrent devices
on its load side.
(3) The tap conductors are protected from physical damage
by being enclosed in an approved raceway or by other
approved means.