AC disconnect vs General Disconnect

[Keepyoucool2003]

I generally work on HVAC and controls, I do have my NEC book and it seems I’m hung up on disconnects. I’ve searched and the only related I found was a post where the OP was using an AC disconnect for a solar installation.

What makes an “ac” disconnect different than a general duty disconnect.

I point to the typical low budget ac disconnect with the pull out such as DPF222 and the molded case enclosed type such as QO200TR

The SD sped sheet refers to it in one section as an AC disconnect and later on the sheet, general purpose.

Are they mixing marketing terms with listed use?

Thank you.

 

[jim dungar]

An AC disconnect t is simply a marketing term for a general disconnect sold at a special price. This is just like term loadcenter which both the NEC and UL term consider a panelboard.

Our industry has decided that AC disconnects should be small and cheap.

 

[jaggedben]

AC =
Air Conditioning?
or
Alternating Current?

In solar, AC disconnect means 'alternating current' and is used to distinguish from a 'DC disconnect' that disconnects direct current circuits connected to solar panels which have DC output. An 'AC disconnect' is on the output of the inverter.

Typical general duty disconnects are not rated to be used with DC, especially not 300-1500V DC that can be found in some solar systems. (Mostly commercial or older residential solar systems, nowadays.) So with solar or other DC sources there is difference with technical importance.

On the other hand...
Disconnects marketed for use with HVAC units, where 'AC' means 'air-conditioning', it's just a marketing term like Jim said.

 

[LarryFine]

I have used a 60a A/C pullout as a remote-generator disconnect at the house.

 

[LarryFine]

AC =
Air Conditioning?
or
Alternating Current?

I took it to be an A/C disconnect.

A/C = air conditioning
AC = alternating current

 

[infinity]

I took it to be an A/C disconnect.

A/C = air conditioning
AC = alternating current

I agree or VAC for voltage alternating current.

 

[Keepyoucool2003]

An AC disconnect t is simply a marketing term for a general disconnect sold at a special price. This is just like term loadcenter which both the NEC and UL term consider a panelboard.

Our industry has decided that AC disconnects should be small and cheap.

That’s terrible. I am not a fan of the pull outs, as they are always too low to the ground, trying to reach under the cover getting the plug back in or out troubleshooting. In residential they are the norm I realize. I wager some picky homeowners would not like the ‘bigger look’ of the handle type.

I did just see a new apt/codno development over the holiday using large 12”ish with the red handle on heat pumps. It was shocking as I would have expected the cheapest thing out there in developer builds.

Thank you for the info.

 

[LarryFine]

I did just see a new apt/codno development over the holiday using large 12”ish with the red handle on heat pumps. It was shocking as I would have expected the cheapest thing out there in developer builds.

Mayhaps they're fused switches.

 

[GoldDigger]

I have used a 60a A/C pullout as a remote-generator disconnect at the house.

I have used two pullouts with only on fuse block available to implement an interlock for POCO versus generator feed. Might or might not be Code, but it is very inexpensive and it works fine.

 

[Frank DuVal]

I am not a fan of the pull outs,

Neither am I, so I buy the Square D ones that look like two pole breakers.