Compressor safety, it always bears repeating

[backupbeeper]

Received and installed - and thanks to @u2slow , @PCustoms, and others who pointed this issue out and identified a suitable switch series for my 5 HP compressor (well, so-called 5 HP, of course). New switch (left) is massive compared to previous one that was only rated for 1 HP (right):


Putting switch in new J-box and wiring it took about half an hour.

But before that could happen, changing out the J-box (the new one is oversized and custom made for this switch, which doesn't fit a standard size) was about six hours - I wanted it mostly recessed so I pulled out the panel, scrolled out the opening, and built a backing brace for it.


And the part of this involving removing / reinstalling my compressor panel, which it seems I didn't much design for serviceability and is very hard to get at from behind (compressor sits above it and air reel in back of it), took 4 hours!


Now to get on with the basic premise of this thread - I'll have to add back in a pilot light to indicate it's on!

Wow

That’s organized !

 

[johnre]

That’s organized !

Well, my wife uses a different word - actually, an acronym - for this aspect of me, but I'll take the compliment - thanks!

And it’s really got to be organized, given the available space - as noted upthread, the compressor is in a crawl space in back of and above the panel, not that accessible. I just brought all compressor-related services out to this panel, along with hot water for my cleaning gun, for ease of access. And it all had to fit in between 16” OC framing on the wall in a limited height, so organization was the only way to make this all fit on the panel. The compressor - a 20 gallon "hot dog" style - had to be situated above the top level of the panel, so that the draincock on this panel would work.

I added the mounts on the sides for the various small air accessories and pressure gauges that you see there; they were put wherever they could fit.

And a bonus is that it is recessed and reasonably protected from objects or people bumping into it, avoiding damage or injury.

Now per my post #80 I need to install the LED power supply and mount the LED to the left of the switch; this will make it clear when the compressor is turned on.

 

[Plastikosmd]

Update

Timer switches added w relay

 

[whateg01]

Update

Timer switches added w relay

Is that one of those neutral-less switches?

 

[slackdaddy1]

I'm not understanding the problem here, a 5HP compressor should have a magnetic starter, and then the control wire that goes to the pressure switch is interrupted and all that is required is a normal wall switch, you will need to check the voltage though, most will be line voltage, [240V in your case] but could be 120V, 24V, and 24V maybe AC or DC (depending on the starter). Amp draw will be very small like 100 mA @120V. Then buy a switch with the appropriate voltage/Amp. rating, either lighted or not, as desired. 5HP is going to be a minimum of 20A but normally about 25A, a wall switch at that capacity will be huge, and likely not long of this world.
Are you using a magnetic starter? Square D by Schneider Electric L111N 30 Amp 120/240-Volt Single-Pole Indoor Light Duty Fusible Safety Switch with Neutral https://www.amazon.ca/dp/B00002NB3F?tag=atomicindus04-20 This is a 30Amp. to allow for some inrush current disconnect.
Magnetic Electric Motor Starter Control Single Phase Magnetic Starter Motor Control 3 Phase Motor Starter Electric Motor switches 5 Hp Single Phase 220/240v Electric Motor Starter(for Motors) https://www.amazon.ca/dp/B09DT8NP9K?tag=atomicindus04-20
Harry

Question:
I have a 5hp 230v 2 stage,, has a WEG motor and WEG PESWS starter The coil is 230v,, which of course gets it's power from the 230v 30amp circuit for the compressor.
So any switch that added, wired in series with the coil and air pressure switch,, would need 10 gauge wire?

 

[Plastikosmd]

I don’t know. I had my electrician wire the 220 relay/ control box and switch etc

Is that one of those neutral-less switches?

 

[giddygoat]

South-side Auto in Faribault Mn burned due to this exact issue, a late model builder sales lot, building had a shop with maybe 10-12 car capacity and offices in front. Someone forgot to shut off the compressor over the weekend, something happened, broke a line or or other leak or switch stuck closed they where not sure, but it was determined the compressor over heating started it. He did rebuild and stayed in business.
I have had my compressor pressure switch stick on more than once (Need to replace it). Just good policy to shut it off when your not around. I do the walk around and check that the everything is off, cutting torch and welding tanks are closed, make it a practice not to weld, cut or grind for the last hour in the shop.
Thanks for the idea of a light in a switch as old age and CRS seems to go hand in hand. Going to put next to the main light switch by the door.

 

[PelicanPines]

My compressor is on the first floor... Right under my wife's side of the bed... If I leave it running... She goes outside opens the garage and shuts it off. So I'm set with my setup.

 

[ArcReactorKC]

My compressor is on the first floor... Right under my wife's side of the bed... If I leave it running... She goes outside opens the garage and shuts it off. So I'm set with my setup.

Call that a biological automation.

 

[PoorUB]

Question:
I have a 5hp 230v 2 stage,, has a WEG motor and WEG PESWS starter The coil is 230v,, which of course gets it's power from the 230v 30amp circuit for the compressor.
So any switch that added, wired in series with the coil and air pressure switch,, would need 10 gauge wire?

No! If wired to the coil 14 gauge wire is more than enough. The coil might draw 1/2 amp.

 

[pcmeiners]

Also remember to manually turn off your compressor when flammable fumes will be present in your garage to reduce explosion hazard.
In NYC this is (or was) a law you are suppose to have an upright compressor or an intake from outside to reduce the chance of flammables being introduced into the tank... which no one follows

 

[johnre]

If I leave it running... She goes outside opens the garage and shuts it off. So I'm set with my setup.

Call that a biological automation.

I'd call it a death wish.

 

[PelicanPines]

I'd call it a death wish.

It's all about love... and the fact that she is usually the one that left it on... After filling her tires.

Training is available for what it's worth.

 

[Plastikosmd]

Here is relay side





I like this setup,( thanks to whoever suggested it)

My lines do leak down over 5-6 hrs and trigger the compressor. I had (almost) always shut of ball valve and power to compressor.

One time I didn’t and somehow I suffer a pop off failure.


This will make it more idiot proof (at least until I become a better idiot)

 

[imagineer]

FWIW, this is my solution for not leaving the air compressor on...

D-ILTCOA Light

I need to install a D-ILTCOA light and have a oddball idea. What's a D-ILTCOA light you ask? "Damn, I Left The Compressor On Again" light. Despite leaving myself notes on the shop light switch and making frequent (after welding) 'return to the shop to look for smoke' trips, I still...

www.garagejournal.com

The system has been in use for a couple years now and proven effective. In the case that I do leave the air compressor turned on when leaving the shop, by nightfall there's a very bright red light (a truck dock light, https://signalguys.com/Dock-Lights-Red-Green-SG10-with-LED-Lamps-_p_753.html) illuminated that's very noticeable from inside the house.

 

[slackdaddy1]

No! If wired to the coil 14 gauge wire is more than enough. The coil might draw 1/2 amp.

My thought was: a 30 amp breaker is supply power to the compressor AND the coil,, in the end, if something went wrong in the "starter box", like a short,, the interrupt circuit you add WILL be seeing 115 or 230v AT 30 amps.

 

[PoorUB]

My thought was: a 30 amp breaker is supply power to the compressor AND the coil,, in the end, if something went wrong in the "starter box", like a short,, the interrupt circuit you add WILL be seeing 115 or 230v AT 30 amps.

You don't size wire for the potential failure. You size it for the load. What size are the existing wires on the control circuit? They certainly are not 10 gauge!

Also, a short on 14 gauge wire the 30 amp breaker will trip before the wire fries.

 

[micromind]

Code wise, motors and control circuits are different than other circuits.

The power wire to a motor is based on the full-load current of the motor as listed in the various tables in the code, not the nameplate current. Breakers and fuses can almost always be larger than the normal wire size allows.

For example, it's perfectly code compliant for a 1HP single phase motor operating at 115 volts to be supplied with #14 copper wire and be protected by a 40 amp single pole breaker.

The breaker does not protect the wire from overload, the motor overloads do. It protects against short circuit and ground fault.

Controls are similar. NEC table 430.72(B) allows #16 wire that does not live the controller enclosure to be connected to the motor power circuit and be protected by a 40 amp breaker. If it leaves the enclosure, the breaker size is reduced to 10 amps. For #14, it's 100 amps in the enclosure and 45 amps if it is outside.

The answer to the question in post #85 is #14.

 

[Shootinok]

I'm usually so good about turning off my air compressor when I'm done using it—until I'm not!
Darn, if I didn't leave it on this weekend. Came home last night and could hear it running, so I went to investigate. The whip hose connecting it to the reel had failed and blown a hole in itself. I'd been in the shop just before 6 a.m., so the longest it could have been is about 12 hrs. The compressor seems OK and wasn't even very hot, so I may have been really lucky this time.
New routine - Disconnect everything! Then, turn it off.

 

[whateg01]

I'm usually so good about turning off my air compressor when I'm done using it—until I'm not!

Every time the subject of automatically turning off the compressor is brought up, there's no end to the people saying "I've never had a problem". Yup, nobody ever has any problem until they do. Glad it wasn't catastrophic for you.

 

[Wrench97]

Had that happen at work once, came in monday morning and both compressors were running, fixed the broken pipe and changed the oil in both they lived another 10 years til I retired.....

 

[4x4Pete]

I wired in two start/stop stations with led indicators as the compressor is in the attached garage and piped out to the shop. 24v circuit with thermostat wire running between the buildings. It operates a relay in series with the pressure switch. I can turn it on or off from either place, and the indicator shows that it's armed at either as well. Almost foolproof. Nothing is foolproof with distractions, though.

 

[seagravedriver]

Stuff like that is why I put mine on a bathroom timer. Twist the knob for about as many hours as I expect to be using air. I don't have to remember to turn it off, which is a good thing considering how easily I get distrac - hey look, a squirrel!

I was a full time firefighter for decades. I was on at least 5 house or apartment fires due to dirty fans that were left on while people were away or asleep. Granted, it is not an air compressor, but something timing out is not a bad thing. I like squirrels!

 

[whateg01]

... Almost foolproof. Nothing is foolproof with distractions, though.

That's why my plan, when I get the rewiring done in my garage is to put the compressor on a timer. Push a button to turn it on and it will stay on, running as needed for, say, 4 hours. Then it turns off unless I reset the timer. I don't use the compressor all day every day like a commercial shop would do I think it'll be fine.

 

[4x4Pete]

That's why my plan, when I get the rewiring done in my garage is to put the compressor on a timer. Push a button to turn it on and it will stay on, running as needed for, say, 4 hours. Then it turns off unless I reset the timer. I don't use the compressor all day every day like a commercial shop would do I think it'll be fine.

Not a bad idea to have an indicator as well. Proof that the timer has shut off.

 

[Glemon]

I had a Sears Craftsman oiless compressor in the garage which was about 7 feet from the house. Our bedroom was on the garage side. If I ever forgot to turn off the compressor before I went to bed it would wake us up when it kicked on. Even if it wasn't noisy was never comfortable leaving a compressor on. Always interesting reading hear about different ideas people have about safety and what to leave on or off.

Somebody said something about not leaving rechargeable batteries plugged in. Never occured to me, I am not in the shop long enough for things to charge back up for the most part if I did that. I suppose there is somewhat of a safety hazard involved, I don't necessarily change how I do things, but always interesting to hear and learn about things from a different angle.

 

[john.k]

The plastic mould shop down the hill from mine used to leave everything going unattended all the time.......one time there was a flood ,his compressor was running half submerged...............i never left anything on,only one outside security light.............incidentally ,on another forum is a guy lost a million$ worth of veteran cars when a computer caught fire while left charging overnight.

 

[whateg01]

The plastic mould shop down the hill from mine used to leave everything going unattended all the time.......one time there was a flood ,his compressor was running half submerged...............i never left anything on,only one outside security light.............incidentally ,on another forum is a guy lost a million$ worth of veteran cars when a computer caught fire while left charging overnight.

What is a veteran car?

 

[john.k]

Made before 1914.

 

[whateg01]

Made before 1914.

Thanks! I learned something today.

 

[Fixr]

I actually think tying the compressor into the shop/garage lights is probably about as good as it gets, except for a timer that can only be started once the lights are turned on. I could have done that, but the simple timer that only runs after I twist the knob regardless of lights is probably good enough for my usage. All of those probably call for a timer and contactor, so maybe not for everyone.

 

[whateg01]

I actually think tying the compressor into the shop/garage lights is probably about as good as it gets, except for a timer that can only be started once the lights are turned on. I could have done that, but the simple timer that only runs after I twist the knob regardless of lights is probably good enough for my usage. All of those probably call for a timer and contactor, so maybe not for everyone.

I don't always turn on the lights and sometimes I leave them on all night. Still could work for some people though.

 

[racecougar]

Always interesting reading hear about different ideas people have about safety and what to leave on or off.

It's typically either ignorance to the hazard(s) at hand or the thought that it won't happen to them. Case in point:

Somebody said something about not leaving rechargeable batteries plugged in. Never occured to me, I am not in the shop long enough for things to charge back up for the most part if I did that. I suppose there is somewhat of a safety hazard involved, I don't necessarily change how I do things, but always interesting to hear and learn about things from a different angle.

 

[M.Brane]

Both power, and main tank valve get shut off when I am done using it.

Batteries do not get left on chargers unless they are outside.

 

[john.k]

The Fire Service guy on telly says all lithium batteries should be charged outside of a building or in a fire proof enclosure............the chinese e scooters and e bikes burn down one house every night.......plenty of utubes of the things on fire.