Air Compressor power supply

[Ken Mac]

If the pallet is well built (ya never know) just attach wheels under that while it's on the forks. (.. and be sure it's still strapped from tipping off them if/when you do. ... disclaimer)

My tank drain is piped out to the edge of the pallet with a shut-off, and there's ample room to slide a can or pan below that when I do the chore. (2-stage compressor, bandsaw, drill press, shop crane, and several work tables/benches have had wheels from day one. Shop press and table saw will sport them soon, as well as a planned dolly for the grapple.)

Anyway, IMO the ultimate electrical protection for the OP's compressor would be to install a separate, lockable, fused disconnect. Fuses rated for 'motor' use (time delay) might save the motor from itself if/when things go awry. (motor stall, etc) This type fuse (usually cartridge, btw) will allow motor start surges (brief, but ~ x7 FLA) but fully protect the motor if power wire/plug is sized to the load vs the main's '50/60?' amps.

A plug for that specific amperage would be best on/in that 'box'. Other guys on the main circuit still draw as they're wired/fused. My 230v mill & lathe are wired this way as std shop practice. (tho' w/o plugs) tog

This is the way wee do it for commercial HVAC. Everything is properly protected this way.

 

[buickanddeere]

This is the way wee do it for commercial HVAC. Everything is properly protected this way.

The supply breaker's role is to only trip if subjected to a short circuit or an extended period of locked rotor current. Thermal protection from overload is only from the compressor motor's thermal protection located in the starter.

 

[bigtiller]

Now, for an update;

I decided to have an electrician do the wiring. He said the load should be about 80% of the power supplied so he swapped the 60 map breaker for a 40 amp. He removed the welding plug, added a 2" extension to the wall box outlet and ran a flex-line to the compressor on/off switch. It looks much better than just running a pigtail to the wall, and I'm glad he did it this way.

 

[445A]

A fine way to spiff up a corner of your shop! Looks nice and clean.:thumbsup:

 

[Mysfyt]

Same compressor that I have in my home shop. Enjoy!

 

[murphy1244]

Now, for an update;

I decided to have an electrician do the wiring. He said the load should be about 80% of the power supplied so he swapped the 60 map breaker for a 40 amp. He removed the welding plug, added a 2" extension to the wall box outlet and ran a flex-line to the compressor on/off switch. It looks much better than just running a pigtail to the wall, and I'm glad he did it this way.


View attachment 470325

I used a HVAC 6 awg whip with a 40 amp breaker. He made his lead a tad long for a bolt down mount.

 

[bigtiller]

I used a HVAC 6 awg whip with a 40 amp breaker. He made his lead a tad long for a bolt down mount.

The lead length was my decision, because.... Also hanging on the wall is the drop cord to connect my generator to the transfer switch. I wanted the compressor power cable to be below the generator cable so it would be out of the way when i needed to hook up the generator during a power outage.

 

[buickanddeere]

Now, for an update;

I decided to have an electrician do the wiring. He said the load should be about 80% of the power supplied so he swapped the 60 map breaker for a 40 amp. He removed the welding plug, added a 2" extension to the wall box outlet and ran a flex-line to the compressor on/off switch. It looks much better than just running a pigtail to the wall, and I'm glad he did it this way.


View attachment 470325

Don't know why he would swap out the existing 60amp for a 40amp ? The 60 amp is entirely legal according to code.

 

[bigtiller]

Don't know why he would swap out the existing 60amp for a 40amp ? The 60 amp is entirely legal according to code.

Maybe it was because of the size of the wire? The switch box on the compressor is only 4" tall, 2.25" wide and thick. It gets awfully busy in there with 2 clamp connectors, 3 wires in, 3 wires out and the on/off switch.

 

[the old grind]

A 60A in the panel is OK to protect proper wiring to an outlet, but when hard-wired as bt's compressor is I would go with the motor rating* (FLA*) or the fixed lead to it, whichever is lower, for a safety margin.

* On many of our shop machines we use 'motor rated' fuses (time delay .. remember 'Fusestat'?) that will allow the x7 starting surge (<.5 sec) but blow at the continuous rating over a reasonably short time. We're doing similar to home AC units with a fused (or breaker) disconnect wired directly at the appliance.

2HP Lathe, 230v/30a panel/disconnect w/lockout (a must when servicing such, and to prevent unauthorized use.)



The line(s) is/are 12ga, with a 20a common trip breaker at the distribution panel.
(btw, I can hold a thou' tolerance on the lathe, but can't hold a camera/cel steady. )

bigtiller, that's a nice looking setup, room to hang the gen cable, and room to tidy around the big 'Q'. :thumbsup:

Note the mag starter and pop-off on the 1st stage. (Safety, folks!)

 

[bigtiller]

I overheard a discussion between the electrician and his apprentice about a lockout-disconnect. He said it wasn't necessary because the main breaker panel is close enough.

 

[buickanddeere]

Maybe it was because of the size of the wire? The switch box on the compressor is only 4" tall, 2.25" wide and thick. It gets awfully busy in there with 2 clamp connectors, 3 wires in, 3 wires out and the on/off switch.

40 amp and 60 amp breaker are the same physical size.

 

[buickanddeere]

A 60A in the panel is OK to protect proper wiring to an outlet, but when hard-wired as bt's compressor is I would go with the motor rating* (FLA*) or the fixed lead to it, whichever is lower, for a safety margin.

* On many of our shop machines we use 'motor rated' fuses (time delay .. remember 'Fusestat'?) that will allow the x7 starting surge (<.5 sec) but blow at the continuous rating over a reasonably short time. We're doing similar to home AC units with a fused (or breaker) disconnect wired directly at the appliance.

2HP Lathe, 230v/30a panel/disconnect w/lockout (a must when servicing such, and to prevent unauthorized use.)
View attachment 470392
View attachment 470393

The line(s) is/are 12ga, with a 20a common trip breaker at the distribution panel.
(btw, I can hold a thou' tolerance on the lathe, but can't hold a camera/cel steady. )

bigtiller, that's a nice looking setup, room to hang the gen cable, and room to tidy around the big 'Q'. :thumbsup:

Note the mag starter and pop-off on the 1st stage. (Safety, folks!)

The hard wired in particular make it legal to use the 60 amp breaker and prevent Nuisance trips. A 40 amp breaker doesn't trip any faster on a dead short than a 60 amp. Not making anything "safer". The motor thermals protect from overloads.

 

[murphy1244]

How do you like it so far? Is it loud?

 

[bigtiller]

How do you like it so far? Is it loud?

I'm liking it. More air than I have ever had! It is rather loud but it is a good kind of loud. A large, heavy machine type of loud. When it comes on, you know it isn't a $500 Sears model.

I broke it in today. I put a 1/4" hose barb on the end of the hose, turned the regulator down to about 45, started it up and let it run continuously for 75 minutes. After it cools off I will re-torque the head bolts - per the owners manual.

 

[the old grind]

A motor's thermal internal o'load bits protect it from o'heating, regardless of the cause, and it's the not the only thing that can happen. Fuses are to protect wires, not loads. (Where did speed of trip even come from?) A fuse/breaker is to protect the smallest wire hard-wired to and beyond it, nothing more or less. (not 'plugged in', you're on your own there)

IMO the OP's connection setup is better than most I've seen. (my own compressor is no example, btw ... just yet ... )

That said, a short in the OP's wiring at the motor will subject all wiring to it to as much as the breaker will pass w'out tripping, presuming all of it has the ampacity. If the OP's leads from wall box to motor are 10ga or 12ga they would become the fuse vs a 60A breaker at the main panel that could fry them. (Just sayin', and neither here nor there.

If one isn't familiar with slow-blow or time-delay fuses and their specific use on motors this all may mean even less. (btw: ... what the magnetic starter is for ... to disconnect if power is interrupted and require a manual restart. Stuff happens or we wouldn't have generators.)

This is not to criticize what bt has set up or to disagree with any comments put forth here. We each have our own methods. (Some folks disconnect seat switches ) Some of us have 'blanket' liability insurance above our farm/home policies. Some have none at all. I hereby confess to using 40w bulbs in desk lamps that are UL approved for 60w ones, and driving ~5 mph below local speed limits when nobody is behind me, so I suggest that my comments not be taken too seriously.

 

[bigtiller]

old grind, that's why I hired an electrician. He knows all that stuff and he is the one who wired my house when it was built. I knew I could do it, and I appreciate all the help from my tractor buddies, but I decided my insurance agent would rather see a pro do it than a retired home owner with nothing better to do.

 

[the old grind]

... I hired an electrician. He knows all that stuff and he is the one who wired my house when it was built ... I decided my insurance agent would rather see a pro do it than a retired home owner ...

IMO, this is easily as important as our suggestions, questions, and examples. (A really good thread title salute will get views from ___ in cyberspace, and ought to stand out a bit and be considered by anyone reading this far.)

Oh, and might there also be a warranty requirement specifying 'proper installation'?" (ie: adequate 'power supply'.) :scratchchin:

IMO, its usually wise to go with the guy actually 'looking under the hood'. Yours also knows what you have (in all) and how best to connect to it. ... and I'd bet he also knows how to avoid callbacks and insurance claims. (... apologies for 'trade' humor ..)

 

[buickanddeere]

A motor's thermal internal o'load bits protect it from o'heating, regardless of the cause, and it's the not the only thing that can happen. Fuses are to protect wires, not loads. (Where did speed of trip even come from?) A fuse/breaker is to protect the smallest wire hard-wired to and beyond it, nothing more or less. (not 'plugged in', you're on your own there)

IMO the OP's connection setup is better than most I've seen. (my own compressor is no example, btw ... just yet ... )

That said, a short in the OP's wiring at the motor will subject all wiring to it to as much as the breaker will pass w'out tripping, presuming all of it has the ampacity. If the OP's leads from wall box to motor are 10ga or 12ga they would become the fuse vs a 60A breaker at the main panel that could fry them. (Just sayin', and neither here nor there.

If one isn't familiar with slow-blow or time-delay fuses and their specific use on motors this all may mean even less. (btw: ... what the magnetic starter is for ... to disconnect if power is interrupted and require a manual restart. Stuff happens or we wouldn't have generators.)

This is not to criticize what bt has set up or to disagree with any comments put forth here. We each have our own methods. (Some folks disconnect seat switches ) Some of us have 'blanket' liability insurance above our farm/home policies. Some have none at all. I hereby confess to using 40w bulbs in desk lamps that are UL approved for 60w ones, and driving ~5 mph below local speed limits when nobody is behind me, so I suggest that my comments not be taken too seriously.

Looks them durned fool engineers who wrote the national electrical code are wrong and you are right .

 

[buickanddeere]

A motor's thermal internal o'load bits protect it from o'heating, regardless of the cause, and it's the not the only thing that can happen. Fuses are to protect wires, not loads. (Where did speed of trip even come from?) A fuse/breaker is to protect the smallest wire hard-wired to and beyond it, nothing more or less. (not 'plugged in', you're on your own there)

IMO the OP's connection setup is better than most I've seen. (my own compressor is no example, btw ... just yet ... )

That said, a short in the OP's wiring at the motor will subject all wiring to it to as much as the breaker will pass w'out tripping, presuming all of it has the ampacity. If the OP's leads from wall box to motor are 10ga or 12ga they would become the fuse vs a 60A breaker at the main panel that could fry them. (Just sayin', and neither here nor there.

If one isn't familiar with slow-blow or time-delay fuses and their specific use on motors this all may mean even less. (btw: ... what the magnetic starter is for ... to disconnect if power is interrupted and require a manual restart. Stuff happens or we wouldn't have generators.)

This is not to criticize what bt has set up or to disagree with any comments put forth here. We each have our own methods. (Some folks disconnect seat switches ) Some of us have 'blanket' liability insurance above our farm/home policies. Some have none at all. I hereby confess to using 40w bulbs in desk lamps that are UL approved for 60w ones, and driving ~5 mph below local speed limits when nobody is behind me, so I suggest that my comments not be taken too seriously.

Looks them durned fool engineers who wrote the national electrical code are wrong and you are right .