Condensing unit internal fuses meet OCPD requirements?

[wwhitney]

In my view, you are still looking at a branch circuit. The "outlet" is where the premises wiring conductors attach to the built-in disconnect.

Seems to me that would depend a bit on the details of the built-in disconnect.

For example, if an installer of a roof-top HVAC unit bolts a separate fused disconnect to the side of the HVAC unit, and then runs a feeder to the disconnect, and runs a short branch circuit from the disconnect to the HVAC unit's terminals, that's all fine, right?

If instead the manufacturer will sell you the HVAC unit with that same fused disconnect bolted onto the side, and the same conductors preinstalled from the fused disconnect to the HVAC unit's terminals, the end result is identical. So you'd still have a branch circuit from the disconnect to the HVAC unit's terminals.

But that may not be what the OP has.

Cheers, Wayne

 

[mtnelect]

The only time I have seen internal fuses on a HVAC unit, is when Emergency Heat is involved. On a split system it would be found inside the Air Handler of a Heat Pump, or inside of a HVAC package unit Heat Pump and it would be on its own circuit. Also, disconnects must be acceptable and having to removed panels is not considered accessible.

 

[alehman]

In my view, you are still looking at a branch circuit. The "outlet" is where the premises wiring conductors attach to the built-in disconnect.

So if the disconnect with 15A fuses was mounted next to the unit rather than in the control panel, the answer would be different? Not being argumentative. I can see both side of this, which is why I posted here.

 

[mtnelect]

Seems to me that would depend a bit on the details of the built-in disconnect.

For example, if an installer of a roof-top HVAC unit bolts a separate fused disconnect to the side of the HVAC unit, and then runs a feeder to the disconnect, and runs a short branch circuit from the disconnect to the HVAC unit's terminals, that's all fine, right?

If instead the manufacturer will sell you the HVAC unit with that same fused disconnect bolted onto the side, and the same conductors preinstalled from the fused disconnect to the HVAC unit's terminals, the end result is identical. So you'd still have a branch circuit from the disconnect to the HVAC unit's terminals.

But that may not be what the OP has.

Cheers, Wayne

I have never seen a factory supplied disconnect shipped with the HVAC unit, always must be field supplied.

 

[alehman]

The only time I have seen internal fuses on a HVAC unit, is when Emergency Heat is involved. On a split system it would be found inside the Air Handler of a Heat Pump, or inside of a HVAC package unit Heat Pump and it would be on its own circuit. Also, disconnects must be acceptable and having to removed panels is not considered accessible.

It's a condensing unit for a computer room split system, with a control panel that can be opened with 3 screws.

 

[mtnelect]

It's a condensing unit for a computer room split system, with a control panel that can be opened with 3 screws.

You still need an external disconnect, before you remove just one screw to gain access. The power must be disconnected before working on the unit.

 

[Elect117]

I think they need to swap it with a 15A MCCB breaker.

You still need an external disconnect, before you remove just one screw to gain access. The power must be disconnected before working on the unit.

The local disconnect from the first photo isn't good enough? I think when the door is closed, the switch lines up with the handle in the second photo. I thought that was okay.

You could always make the breaker lockable, no?

And there should be a receptacle near this for servicing.

 

[alehman]

You still need an external disconnect, before you remove just one screw to gain access. The power must be disconnected before working on the unit

I don't think there's anything in the NEC that requires an external disconnect.

 

[mtnelect]

How about NEC 440.11

 

[alehman]

I think they need to swap it with a 15A MCCB breaker.



The local disconnect from the first photo isn't good enough? I think when the door is closed, the switch lines up with the handle in the second photo. I thought that was okay.

You could always make the breaker lockable, no?

And there should be a receptacle near this for servicing.

Yes, the handle you see in the first photo lines up with a shaft from the internal switch which is mounted to the left of the fuse block, out of sight, in the 2nd photo. The breaker could be made lockable if required by the NEC (I don't think it is required). There is a GFCI-protected weatherproof convenience receptacle within 25 ft.

 

[alehman]

How about NEC 440.11

"Disconnecting means shall be capable of disconnecting air-conditioning and refrigerating equipment, including motor-compressors and controllers, from the circuit conductors. If the disconnecting means is readily accessible to unqualified persons, any enclosure door or hinged cover of a disconnecting means enclosure that exposes energized parts when open shall require a tool to open or be capable of being locked."

I think the installation complies with this.

 

[mtnelect]

Also, NEC "Raintight" Constructed or protected so that exposure to a beating rain will not result in the entrance of water under specified test conditions. I would not install it exposed to weather, the first rainstorm it would be filled with water.
Also NEC "Weatherproof" and "Watertight"

 

[qcroanoke]

I don't think there's anything in the NEC that requires an external disconnect.

The language used to be (can be mounted on or a part of). Not sure what it says now.

 

[qcroanoke]

Also, NEC "Raintight" Constructed or protected so that exposure to a beating rain will not result in the entrance of water under specified test conditions. I would not install it exposed to weather, the first rainstorm it would be filled with water.
Also NEC "Weatherproof" and "Watertight"

Not sure what you're referring to.

 

[mtnelect]

Not sure what you're referring to.

The label on the unit states "Suitable for Outdoor use" is not a NEC term.

 

[PaulEd]

From NEC 2020 Handbook, 440.21

Enhanced Content:

"If supplemental overcurrent protection is provided within the heating, air conditioning, and refrigeration (HACR) equipment control panel, the manufacturer will have marked the equipment with specific information on the type of branch-circuit overcurrent protective device that can be used on the line side of the HACR unit in order to provide the necessary level of short-circuit and ground-fault protection for the equipment and controls internal to the HACR unit."

If the equipment is marked with 15A MOCP that is most likely for the ground fault protection based on how the handbook words it.

Doesn’t this, effectively, end the debate?

 

[mtnelect]

Doesn’t this, effectively, end the debate?

I now agree, after seeing the pictures of the unit.

But, now after seeing pictures of the unit, I have additional questions:
1) The term "Suitable for Outdoor use" is not a NEC term.
2) The unit doesn't look "Suitable for Outdoor use".

 

[PaulEd]

I now agree, after seeing the pictures of the unit.

But, now after seeing pictures of the unit, I have additional questions:
1) The term "Suitable for Outdoor use" is not a NEC term.
2) The unit doesn't look "Suitable for Outdoor use".

1) it’s manufacturers spec
2) if it says it’s suitable for outdoor use I’m sure it is. Do we need to 2nd, 3rd, or 4th guess every minutia and parse ever sentence ?

It’s my understanding that whatever is on the nameplate of hacr equipment is what we install. I’m not sure why this question was ever asked to begin with

 

[alehman]

It's a condensing unit from a major U.S. manufacturer. It's intended and labeled for outdoor use. If it leaks that will be warranty issue.