compressor jbox or disconnect question

[shannonw]

Hey all,

i'm relocating my compressor yet again. Right now it's hard wired from the panel. Where i'm putting it i need to run conduit down a wall. My question is currently there is a square d pressure switch (no manual switch) on the compressor. Should i just run a junction box at the end of the conduit to the compressor or put a disconnect there?

it's all in line of sight of the panel, i'm just not sure if technically the disconnect may be better to turn on/off vs the breaker, i seem to recall reading on here a few times using the breaker is not recommended especially if it's under load.

 

[C96]

Put in the disconnect switch, make sure it is the correct rating for your compressor. If your compressor is controlled via a mag starter, you can wire a switch in series with the coil on the control relay.

 

[teamextreme]

Code says it has to have a disconnect switch within 50ft and within sight. If your breaker meets these 2 criteria, then it's fine without a local disconnect switch. Is it better to have one? Maybe, maybe not. In 20-some years of having a compressor I can't think of once I needed to kill power that flipping the pressure switch didn't accomplish what I needed. So you have to ask yourself if the added expense that exceeds code requirements is really necessary.

 

[shannonw]

thanks for input, the square d pressure switch doesn't have a 'manual' switch, nor is it a mag starter. I just use the breaker though, it's rare i turn it off under load. but i do turn it on by the breaker.

i'm in sight , only 15 feet away so that's not an issue code wise.

Mainly need a jbox or disconnect just to have something the conduit can fit in instead of just running a romex through a flex cable hanging out of drywall. I'd do a jbox to clean that up but if there's an advantage to a disconnect may do that.

Either way seems a 10hp disconnect only looks like a few bucks for the correct hp and amps (5hp 21 amp compressor motor)

 

[b-body-bob]

When I upgraded compressors I used a square D disconnect from either Lowe's or Home Depot, with 30A slow-blow fuses. It wasn't cheap but it wasn't real expensive either. I feel better turning that off instead of the breaker, since the disconnect is meant to be turned off and on but a breaker really isn't.

 

[shannonw]

b-body-bob, Sounds like a good idea, i think that's what i recall reading on here and is the general suggestion vs a breaker. Given the cost isn't much i'll just wire a disconnect in there, couple extra bucks for some additional peace of mind.

 

[Norcal]

Use a pullout A/C disconnect, they can be bought under $10, and come in 3 flavors, 30A & 60A fusible & 60A non fusible.