Ductless Mini Splits AC Interconnect Wiring....

[stickboy1375]

I've always used 14-3 UF when wiring these types of units, but i've been seeing a lot of AC guys using 18-4 CL2 shielded wiring for this interconnect....

Here is an example of a typical unit, http://us.sanyo.com/dynamic/product/Downloads/30.36KHS82 Installation Instructions-39363246.pdf

3-7 is the electrical part in the pdf....

 

[iwire]

Looks like 14 AWG minimum for this particular unit.

Table 5 / Fig 23

 

[stickboy1375]

Looks like 14 AWG minimum for this particular unit.

Table 5 / Fig 23

Required to be a chapter 3 wiring method though, correct?

 

[Dennis Alwon]

I have a real problem with some of these units. I have seen the manufactures provide a rubber cord from the indoor unit to the outdoor unit. I have seen the a/c guys run it thru the walls to the unit. I believe these cords were meant to run exposed on the exterior of the building not thru the walls since it is prohibited by 400.8.

Some of these units are 24V DC motors and only need a thermostat wire to operate from. I don't see that as an issue. We provide power to the outdoor unit and that's it.

 

[iwire]

Required to be a chapter 3 wiring method though, correct?

I really don't know.

 

[Dennis Alwon]

Be careful I have seen an outdoor unit that was rated 120V. We just assumed 240v. I couldn't believe we didn't fry the unit.

 

[stickboy1375]

I have a real problem with some of these units. I have seen the manufactures provide a rubber cord from the indoor unit to the outdoor unit. I have seen the a/c guys run it thru the walls to the unit. I believe these cords were meant to run exposed on the exterior of the building not thru the walls since it is prohibited by 400.8.

Some of these units are 24V DC motors and only need a thermostat wire to operate from. I don't see that as an issue. We provide power to the outdoor unit and that's it.

I believe they expect those rubber cords to be run through the building, why else would they even supply them, and just like my towel bar thread, probably not a 400.8 issue...

 

[stickboy1375]

Be careful I have seen an outdoor unit that was rated 120V. We just assumed 240v. I couldn't believe we didn't fry the unit.

That was a nice surprise... I had that happen with a few water heaters.

 

[iwire]

I believe they expect those rubber cords to be run through the building, why else would they even supply them, and just like my towel bar thread, probably not a 400.8 issue...

I am just going to ramble, it seems in other countries cords are used much more than here. I think that they may well have intended the cords to be run through walls but I also think that here in the US that is a problem and one of the reasons why the electrical instructions you linked to say

3-7. Wire Size and Length
Regulations on wiring diameter differ from locality to locality. For field wiring requirements, please refer to your local electrical codes. Carefully observe these regulations when carrying out the installation.

 

[stickboy1375]

I am just going to ramble, it seems in other countries cords are used much more than here. I think that they may well have intended the cords to be run through walls but I also think that here in the US that is a problem and one of the reasons why the electrical instructions you linked to say

I'll agree to that... I'm sticking with using 14-3 UF for my installs, if the AC guy runs the wire, so be it...

 

[Dennis Alwon]

I believe they expect those rubber cords to be run through the building, why else would they even supply them, and just like my towel bar thread, probably not a 400.8 issue...

I thought the towel bar used the cord inside the unit and not thru the walls. I would have an issue with that.

Also just because an item is UL listed does not mean it is necessarily code compliant. UL does not test for code compliancy but rather for safety and what the customer asks them to test for.

 

[augie47]

Many of those units in this area are supplied with TC cable. The installers were slowly convinced that (a) TC cable needed to be in an approved raceway when inside a residence and (b) a switch is required at the inside unit to disconnect the motor.

 

[Ponchik]

if it is UL approved "as is" with the cord that came with the unit, then wouldn't you assume that it is ok to use inside? regardless what the NEC states.
Now if the unit didn't come with the cord and it was installed with a cord then it is a violation of NEC.

 

[iwire]

if it is UL approved "as is" with the cord that came with the unit, then wouldn't you assume that it is ok to use inside? regardless what the NEC states.

No, I do not assume that.

 

[kwired]

I've always used 14-3 UF when wiring these types of units, but i've been seeing a lot of AC guys using 18-4 CL2 shielded wiring for this interconnect....

Here is an example of a typical unit, http://us.sanyo.com/dynamic/product/Downloads/30.36KHS82 Installation Instructions-39363246.pdf

3-7 is the electrical part in the pdf....

My question is if using CL2 cable is it a CL2 circuit? If it is supplying a blower motor even though it may only be 24 volts, it likely exceeds power limitiations for class 2 circuits, and therefore is not a class 2 circuit.

 

[stickboy1375]

I thought the towel bar used the cord inside the unit and not thru the walls. I would have an issue with that.

.

No, the cord has to be run inside a wall cavity.... I have a problem with it also... the GC was actually pissed at me because I really didn't have a solution for him, and he made the phone call to the company selling the product and they said it was fine, so now it looks like I'm the idiot... what ever...

 

[stickboy1375]

My question is if using CL2 cable is it a CL2 circuit? If it is supplying a blower motor even though it may only be 24 volts, it likely exceeds power limitiations for class 2 circuits, and therefore is not a class 2 circuit.

I don't know why the AC guys picked the wire that they did, all I can tell you is that its a 240v plus a conductor to turn the outdoor unit on/off.... the inside blower motor draws .40 of an amp.

 

[stickboy1375]

Many of those units in this area are supplied with TC cable. The installers were slowly convinced that (a) TC cable needed to be in an approved raceway when inside a residence and (b) a switch is required at the inside unit to disconnect the motor.

Yeah, I still haven't been able to get guys to install an interior disconnect yet, but Im not the inspector so its really not my issue, I can only do so much.

 

[Ponchik]

No, I do not assume that.

But, if it would a code violation or a hazard then why would UL or other testing agency approve and list the product with the cord? knowing that the cord is being installed indoors? It is like the oven or the cook top that comes with a whip with only #12 AWG but the circuit must be rated for 40 or 50 Amps? Do we change the conductors in the whip too? or it is approved and listed "as is"

:? I don't know, i am just asking.

 

[stickboy1375]

But, if it would a code violation or a hazard then why would UL or other testing agency approve and list the product with the cord? knowing that the cord is being installed indoors? It is like the oven or the cook top that comes with a whip with only #12 AWG but the circuit must be rated for 40 or 50 Amps? Do we change the conductors in the whip too? or it is approved and listed "as is"

:? I don't know, i am just asking.

The insulation of the conductors on a cook top are high temp, so its a non issue.