Split Unit AC

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blueheels2

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Location
Raleigh, NC
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Electrical contractor
Have you seen the small room AC units? The condensing unit is outside and it is fed by a disconnect. It has a control wire that goes from this unit to the inside unit. This control wire carries 120 volts to power up the unit inside. Has anyone seen a unit like this. The inspector says you need a disconnect inside as well. If the outside disconnect is lockable do you need the disconnect inside.
 
Yes I have wired a few and yes you need a disconnect inside.

The inside disconnect could be a regular toggle switch in an old work box beside the unit.
 
Not sure that is the case Bob ,or not in all cases. Does this blower unit not have an on off switch already?
 
M. D. said:
Not sure that is the case Bob ,or not in all cases. Does this blower unit not have an on off switch already?
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None that I have done (Sanyo or Mistsibishi) have switches that qualify, many don't have any controls, only a remote.
 
If you can lock the WP disco that is outside (this controls the power to the inside unit) why would you need a disco inside.
 
Dennis Alwon said:
If you can lock the WP disco that is outside (this controls the power to the inside unit) why would you need a disco inside.
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If you can see it from the blower unit I think you would be all set.
 
Also be very careful on these units. I did one without looking at the voltage-- surprise--- I had never seen a 120 Volt unit. I wired it 220 and the rest is history---- Actually the service guy caught it but I had it on for over 10 minutes on 220 with the fan running and everything.

Once I switched the voltage to 120 it ran for another 2 months and then gave out. I paid for the small part that burned out. Compressor and inside unit never had a problem.

I might add I had to wire that dam unit in the rain and the heat/ac guy said it was the same units I had wired a month earlier. They were the same brand not the same voltage.
 
M. D. said:
If you can see it from the blower unit I think you would be all set.
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I don't think it has to be in sight.

We do this with well pumps all the time. The disco is at the holding tank where the controls are.
 
"440.14 Disconnecting means shall be located within sight from and readily accessible from...."
 
M. D. said:
"440.14 Disconnecting means shall be located within sight from and readily accessible from...."
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I just read that again--- complete the sentence "from air conditioning and refrigerant equipment." Is the inside blower a/c or a blower?
 
split a/c

split a/c

The ones I have seen have a thermostat controller (without and off position) on the inside unit, Since that is the controller to the fan motor, I required an inside disconenct (wall type toggle switch).
 
augie47 said:
The ones I have seen have a thermostat controller (without and off position) on the inside unit, Since that is the controller to the fan motor, I required an inside disconenct (wall type toggle switch).
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This is from one that plugs in at the inside unit and a disconnect is required to be installed in the inter connect cable


Disconnect switch and circuit breaker for over current protection given in the table below is to be installed between the indoor unit and the outdoor unit.

15A 240 V - 5A


Disconnect switch Circuit breaker (or Fuse)
Click to expand...
 
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I wire around 30 or so each year, interior disconnect required. Or a locking means at the circuit breaker if I am not mistaken also qualifies as an appropriate way to go. I always just put in a switch on the wall near the fan coil unit. So far, no inspector has giged me for having the switch up too high on the wall,( above 6-7") in lots of cases, my guess is they are just happy to see the switch installed.
 
Can anyone think of a reason they would not incorporate a unit switch to serve as the blower disconnect ???
 
Sounds on the money to me. In our market whole house A/C like you guys have is rare, but split A/C units (usually called heat pumps) are very common, and the one I have (professionally installed) is very typical. The outside unit has a disconnect on the wall, and the plumbing and a (from memory) five cord cable goes through a hole in the wall to the inside unit. I figure the five cores are hot, N, G, plus control. I suspect (but never measured) the control is RS485. All the control elements are on the inside unit.

Never seen a disconnect on the inside unit, there isn't anything on the instructions, and there are five wires...
 
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