Wireing house AC condencer unit?

[rodm1]

I have a 25amp air conditioner I need to run wire for. The heating and cooling guy said the max amps are 25amps. Sow I need 10ga wire right with a 30amp breaker? Do I need 3wire cable + ground for outdoors or is 2 wire ok for this install? What kind of disconnect do I need and Is there one I could use to easily plug in a emergency generator with?



https://www.lowes.com/pd/Square-D-60-Amp-Non-Fusible-Metallic-Enclosed-Circuit-Breaker/3364886
http://www.homedepot.com/p/Square-D...e-Over-Current-Protection-QO200TRCP/202353314

 

[wyliesdiesels]

Ok so condenser units are pretty easy.

You size wire by the MCA(minimum circuit ampacity) and size the breaker by the MOP(max overcurrent protection).

Do you know the model number of the unit or have a link?

Or have a pic of the nameplate?

You only need 2 conductor plus ground.

the second link is what you need.

Keep in mind you will also need a 120v service receptacle near by for servicing the unit.

Why is your HVAC guy not doing all this?

You will not be able to combine a generator inlet with this circuit.

Do a separate inlet and circuit for the generator.

 

[dw1]

Not sure where you are located?? but are there any electrical supply houses by you? You can get a 60 amp, No Fuse disconnect like you posted for about $8.00
What brand of electrical panel do you have?? if you buy a 25 amp double pole breaker, most likely you will have to get it at a supply house also (in stock) or probably can get online (order) at HD/Lowes depending on what brand you have.

 

[mikebaker1129]

25 amp sounds like a 2 1/2 or a 3 ton condensing unit.
Run 2 wires(Black) and 1 ground(green) #10 ga wire. Codes vary ,but here in TX a means of disconnect must be with in sight. Which would mean you need a disconnect near the unit as mentioned already.

 

[Norcal]

The local HD has Halex brand 60A non-fusible pull out disco's for under $5. As Wylie stated in post #2, A/C units are wired for the minimum ampacity and use the maximum permitted size overcurrent device, which both are determined by what the data plate on the unit says. This method results in circuit breaker & wire combinations that are not allowed for normal branch circuits but are code compliant if wired to the data plate info.

 

[theoldwizard1]

... Is there a disconnect I could use to easily plug in a emergency generator with?

NO ! An emergency generator can only be feed into a main panel through a generator interlock kit/breaker. The interlock prevents that circuit from being used when the main power is on.

 

[wyliesdiesels]

NO ! An emergency generator can only be feed into a main panel through a generator interlock kit/breaker. The interlock prevents that circuit from being used when the main power is on.

Doesnt have to be a main panel. Can do subpanel but then only subpanel circuits would have gen power.

 

[zmaxmotorsports]

You can buy a disconnect from the supply house that has a gfci built into it to cover both bases.

 

[prostreetamx]

NO ! An emergency generator can only be feed into a main panel through a generator interlock kit/breaker. The interlock prevents that circuit from being used when the main power is on.

You also would need to feed the generator breaker with a 3 conductor cable with ground. A 10/2 with ground wouldn't have a neutral. I had to add a neutral to one of my old A/C disconnects that I converted into an RV plug after I relocated the A/C condenser. Luckily it was pretty close to my sub panel inside the garage. I ran a separate feed into my sub for my generator and will be adding the interlock soon. I would not try to use an A/C feed as a dual purpose item, just buy some extra wire and do it safely.

 

[wyliesdiesels]

You can buy a disconnect from the supply house that has a gfci built into it to cover both bases.

OP- if you go this route, you will need 3 cnd + ground.

You also would need to feed the generator breaker with a 3 conductor cable with ground. A 10/2 with ground wouldn't have a neutral. I had to add a neutral to one of my old A/C disconnects that I converted into an RV plug after I relocated the A/C condenser. Luckily it was pretty close to my sub panel inside the garage. I ran a separate feed into my sub for my generator and will be adding the interlock soon. I would not try to use an A/C feed as a dual purpose item, just buy some extra wire and do it safely.

What kind of wire was used for the existing circuit?

 

[zmaxmotorsports]

OP- if you go this route, you will need 3 cnd + ground.



What kind of wire was used for the existing circuit?

 

[rodm1]

Thanks everyone I think you all cleared up some of the questions I have. I will see if I can get a ID plate or model number.

Here is the spec sheet to the model I'm getting or very close from what he described to me.
See page 8 for the amps I think they are model RA1424W or RA1430W I will call tomorrow to double check the model numbers.

http://cdn.globalimageserver.com/fetchDocument.aspx?id=475a12b0-ef41-40f5-b44a-3f4943a74414

 

[wyliesdiesels]

Thanks everyone I think you all cleared up some of the questions I have. I will see if I can get a ID plate or model number.

Here is the spec sheet to the model I'm getting or very close from what he described to me.
See page 8 for the amps I think they are model RA1424W or RA1430W I will call tomorrow to double check the model numbers.

http://cdn.globalimageserver.com/fetchDocument.aspx?id=475a12b0-ef41-40f5-b44a-3f4943a74414

The 1424 has a MCA of 15a and the 1430 has an MCA of 17a.

You can use #14 for either one.

 

[Norcal]

The 1424 has a MCA of 15a and the 1430 has an MCA of 17a.

You can use #14 for either one.

Unless the 1430 is fed w/ NM cable, then 12 AWG is required.

 

[wyliesdiesels]

Unless the 1430 is fed w/ NM cable, then 12 AWG is required.

why?

 

[Norcal]

why?

14 AWG NM cable has a 15A rating, 14 AWG THWN in that application is 20A.

 

[wyliesdiesels]

14 AWG NM cable has a 15A rating, 14 AWG THWN in that application is 20A.

yeah whoops. of course. I misread what you wrote.

On a side note, Im trying to figure out how OP could legally provide the service receptacle(using a combination disconnect) with the same circuit seeing as the breaker is 25a.

Dont think its possible.

 

[Norcal]

yeah whoops. of course. I misread what you wrote.

On a side note, Im trying to figure out how OP could legally provide the service receptacle(using a combination disconnect) with the same circuit seeing as the breaker is 25a.

Dont think its possible.

I agree, 2 feeds would be required.

 

[prostreetamx]

OP- if you go this route, you will need 3 cnd + ground.



What kind of wire was used for the existing circuit?

In my case I had run 6/2 with ground for the A/C's. I had 2, 3 ton units that I moved to make room for RV parking. Since both were wired with 6/2 copper originally, I surface piped only one of them to the new A/C location and installed a 6 circuit sub panel at that location. I had to add a neutral at that location also since my new sub panel now has a 120v service plug attached to it. The remaining A/C disconnect box was used as a junction box to feed a 50a RV plug. I ran 6/2 originally to both A/C's since the model of my house had one 3.5 ton unit and one 3 ton. Not sure why they installed 2, 3 ton units but they have worked fine for 15 years until I replaced one recently and the second unit is also failing. I fed both wires with 50a breakers after the move. Both were originally fed with 30's before the move. I am an electrician and wire is cheap compared to cutting holes later.

 

[rodm1]

Thanks everyone I think you all cleared up some of the questions I have. I will see if I can get a ID plate or model number.

Here is the spec sheet to the model I'm getting or very close from what he described to me.
See page 8 for the amps I think they are model RA1424W or RA1430W I will call tomorrow to double check the model numbers.

http://cdn.globalimageserver.com/fetchDocument.aspx?id=475a12b0-ef41-40f5-b44a-3f4943a74414

I talked to the AC guy today and he said the RA1424W is one of the options. He said a 2-ton model is adequate.

 

[cory58]

Search function is great! Kept me from asking the same questions again in a new thread.

I'm putting in a 4 ton heat pump with 5kw strip heat. Per the manual, the the MOP is 60 amps and the MCA is 51.3 amps.

Can I use a 60 amp breaker and a service disconnect rated for 60 amps, or do I need to size in some excess capacity?

Is it correct that I size the wire based on the 51.3 amps?

Is the need for a separate 120v service receptacle pretty much universal or does that vary by municipality?

Thanks, Cory

 

[Stuff]

Is that a package unit or split system? Why asking is split would have two separate feeds.

60 amp breaker in panel with 60 amp or higher rated disconnect is fine. The MOP and MCA already figure in excess. Yes, wire size based on MCA.

120 volt receptacle for service is NEC required so yes, universal.

 

[cory58]

Is that a package unit or split system? Why asking is split would have two separate feeds.

60 amp breaker in panel with 60 amp or higher rated disconnect is fine. The MOP and MCA already figure in excess. Yes, wire size based on MCA.

120 volt receptacle for service is NEC required so yes, universal.

Thank you!

It's a package heat pump, so no separate evaporator unit. It also has a single source electrical feed option, so I don't need a separate circuit for the electric heat strips.

Cory