I am going to wire my new Rheem Air Handler myself.
It is 220V. It has two CB's on the front; one 60A and one 30A.
There are a few different size knockouts in the top of the unit.
I would figure that a disconnect adjacent to the air handler is
Back at the meter, I'm going to come off the new 200A meter into a
200A load center which has 4 spaces (it says room for 8 circuits on
It comes with the 200A main CB, and I'll get two 100A/220A CB's.
I want to punch holes in the back of the load center then directly
into the structure. This is OK? How do I attach it to the house. We
have cheezy PVC siding over what I suspect is wood clapboard.
Comments and suggestions?
Did you mean to say 100A/220 VOLT CB's?
One breaker should be enough to handle that air handler's needs, use 1
gauge wire to connect to a disconnect switch adjacent to the air
handler, and from there to the unit.
I'm no code mavin, but the ones on our home were done that way and
passed inspection. Just make sure you use a suitable cable clamp in the
holes, and it would be a good idea to put a blob of silicone caulk
around the clamp before you push the load center against the house, just
to avoid water/insect entry.
How do I attach it to the house. We
I'd go for No. 12 wood screws about 2" long.
Use a non-fused disconnect switch inside. The kind where you pull out a
"shorting plug" works well.
I personally had my fill of fused disconnect switches when one of the
ones on an air handler in our home would fry a fuse every couple of
years because the switch blade contact resistance rose over time and the
heat generated during high current auxillary heater operation would get
conducted to the adjacent fuse end cap. Eventually it would get hot
enough to melt the solder connecting the fuse link to the end cap and
open the circuit. Not a classic "blown" fuse, the link was still whole
and the fibre fuse body was charred to a crisp. <G>
Cleaning the switch contacts and fuse clips and replacing the open fuse
would "fix" things for a year or so, but the problem always came back
the same way. BTW, the disconnect was located in a dry cool area.
I replaced the fused disconnect with a brand new one and after a few
years it started doing the same thing, so I gave up and last summer
replaced it with a non-fused disconnect. So far no problems.
Is the panel rated to have 2-100 amp branch circuits? Check the label on
the inside of the panel if nothing is mentioned on the box. It should say
something like "Maximum branch circuit size....."
Use a hole saw big enough to accommadate the connectors that you will use to
come out the back of the panel. Pull the stripped wire out of the holes.
Put the connectors on the cable without the locknuts. Bring the wire and
connectors into the back of the panel and install the locknuts. Bushings
would be good also. Put duct seal in the holes in the house and around the
connectors and push the panel against the house and screw it to the siding
with long enough screws to catch wood. Use #10 or #12 cadmium plated sheet
metal screws. Be careful not to pull the plastic siding in too much. Put
caulk or duct seal at the top edge of the panel where it meets the siding to
prevent water from getting behind.
This is not as easy as it sounds.
On Mar 10, 4:40 pm, email@example.com (lp13-30) wrote:
Yes I meant 100A/220V breakers. My old meter panel was in place when
they installed the cheezy PVC, the 'framed' around it.
Boltig the new meter panel and outdoor load center up against the PVC
will no doubt distort it, so I was thinking standing the units off the
With a 100A up at the load center, and CB's in the air handler, I was
thinking a fused disconnect would be redundant, and problematic,
although I already have two of these (one for the water pump and one
for the water heater, and never had the problems described.
How do I branch off the disconnect to supply the two seperate breakers
in the Air handler? There is no buss, just 4 cpnnection points; two
for each breaker.
Thanks for the ideas.
This work is by no means easy, but I am experienced in handling thee
materials, I just wanted to get some ideas back from y'all. From
speaking to numerous electricians, there apparently are typically
several ways to do a job and still be doing it right
thanks again for the feedback
How do you plan to do that? You could mount a piece of plywood over the
siding, but that will compress the PVC. The alternative would be to cut out
an opening in the siding, mount a piece of plywood in that and trim out the
siding with the appropriate drip edges and such. Any chance that the new
meter will fit where the old one is now?
I don't think that you need a fused disconnect since the 100 amp line would
be protected by the main breaker. An unfused disconnect should suffice, but
see my response below.
That's a concern. It sounds as though the manufacturer wants two separate
feeds. Check the nameplate and the installation manual. If you don't get
answers there contact the manufacturer for technical support and ask them if
you can feed the unit with one 100 amp line. If it is required to have two
feeds than you should install a small circuit breaker panel near the unit.
You could run both feeds in the same conduit. It is possible that those
internal circuit breakers are just on/off switches and there must be
protection for each circuit outside of the unit.
Can you post some pictures of this puppy so we can get an idea of what
you're dealing with?
I wanted to mount the new meter next to the existing one with a new
mast and the load center in place, then maybe the utility company
could do the switch over on one trip.
Yes I'll contact them. the paperwork for the unit does not seem to
address details on wiring
Yes. But I'm on the run until Friday, so please stay tuned. How do I
do it, attach them? Never mind I'll figure it out.
It was in the 70's around here today so there isn't any huge pressure
to get this project done. besides, it's going to be a few hundred for
the materials, so that puts the brakes on it too. The load center with
the breakers is about $200. The mast and hood and service wire
probably $75. (2" PVC pipe and a hood and the service wire and
clamps). 30' feet of branch wire and the disconnect maybe $100. misc
hardware $20. #4 or #6 solid and clamps to connect the electrode; $10-
A case of beer for the electrical inspector....no no I'm just
but it adds up.
I called Rheem for a little tech support, and they told me to go
screw myself, call an electrician.
The installation instructions for the air handler listed a jumper bar
kit to convert single phase multiple two circuit units to a single
supply circuit. That's what I need
The manual also said the two CB's on the unit are for short circuit
protection of the unit, and not over-current protection and therefore
may be sized larger than the branch circuit protection; the supply
circuit wiring must be 75C minimum copper conductors only; that the
supply circuit protective devices be either fuses or HACR type CB's.
and that an adequate size disconnect should be installed within sight
of and readily accessible to the unit.
So my interpretation is I'll use an HACR in the load center; copper
for the branch; A 100A disconnect near the air handler, and get the
jumper bar kit to keep it Kosher.
There is a copper wire size chart in the Rheem book. Thusfar I'm
understanding it to say that for a 50' wire run, for a 100A circuit,
use #3. For 110A use #2.
But it also says "wire based on copper conductors 75C minimum rating.
For more than three conductors in a raceway or cable see NEC for
derating the ampacity of each conductor"
Don't I need to run 4 conductors out to the air handler? 2 hots, a
neutral and a ground?
I'm unclear on this detail.
This whole episode started when the heating contractor initially told
me to run a #12 off my existing electrical panel to the air handler
location, and we'd be good to go. I should have realised then, but I
already have an existing branch cicuit that was for the coutside
compressor, and I didn't fully understand the components in a split
heat pump system. (I still don't fully understand, but better)
then he changed his mind when he took a second look.
He must've not figured in the heat strips. The fan will run on the
220V/30A on a #12, but the heat strips are the hogs.
No pix yet it's raining and cold.
Very unprofessional of them. I guess whoever you talked to didn't want to
bother explaining things or didn't want the responsibility if you screwed up
and burned your house down.
The ground doesn't count since it is not normally a current carrying
conductor. Does this unit require a neutral? Most wire sold these days is
rated for 90 degrees Celsius, however you must be concerned with the
temperature rating of the terminals on your disconnects, circuit breakers,
and air handler. The most common rating is 60 degrees for terminals
although some can be 75. I don't think anyone makes 90 degree terminals.
To play it safe, just go with the 60 degree column when sizing your wire.
What does the nameplate on the unit say for maximum circuit ampacity or
maximum fuse size?
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