Help choosing disconnect and 220 planning

[justanengineer]

I am getting ready to run a 220 line out to my garage, currently its 110V 20A outlets + lighting only. Ive gotten away with 110 only since buying the house by running 110-->220 VFDs but am getting ready to bring in the welders and a compressor that will need one, maybe two dedicated 220 circuits. Id like to use a disconnect box with a manual knife switch so that I can kill the compressor and machinery overnight and in emergencies easily.

Do manufacturers make disconnects with the big red kill switch on the side plus circuit breakers or are they fused only? Unfortunately the box store help was anything but, and google isnt giving me any clear answer. Not that it matters, but I do realize I could use a circuit breaker as a disconnect switch, but Im not sure Id trust them to work with potential on-off cycling multiple times daily. Im also entertaining the idea of using a regular box subpanel and a separate disconnect, but would prefer to keep things tidy in one box if possible and not cost prohibitive.

 

[sberry]

You do not need to turn them off and on daily and under load, stay simple and standard here and its 240V. If you have a complicated air system and a potential for leaks turn off ball valve at comp, its so rare to need to start it under load don't lose sleep and try to re invent all this.

 

[justanengineer]

I wasnt planning on switching on-off under load unless in an emergency, just like to use it as a master off switch when Im not there or have guests over. My father always had a master red mushroom push button that was switched off everyday and Ive worked in many similar shops that used them, just good safety practice IMHO. At the moment Ive only got the mill and shaper in the garage, but soon will have those plus the lathe, two weldors, and the compressor, not sure I want to leave it to chance in case anything gets left on accidentally or one of my antique machines has a short when Im not here.

Paranoid of fire and electricity? Yup. Been there, started over, dont want to do it again.

 

[rbjenterprises]

Get lock out plates that fit over your new circuit breakers or just a big inline cut off switch that you can lock off.

http://www.homedepot.com/p/GE-30-am...-Duty-Safety-Switch-TG4321R/202978635?N=bm0h#

 

[sberry]

A welder has a 2 pole switch, its fully disconnected when off, so is an air comp all but the control and same with these other large machines. All this stuff I have of this nature has been plugged in with breaker on for years, some never been turned off, breaker to air comp been off twice in 20 years.

 

[sberry]

The reward for the risk reduction is so infintismal that its not even likely a way to calculate factor for a better way of wording it. If it make any kind of difference the code would call for it. Anything with an off/on switch is super reliable.

Maybe your Dad had extra stuff he got for free but you are way more likely to get hurt installing the extra stuff than reduce any potential accident, danger multiplied if you have to pull out on the hiway to get parts..

 

[sberry]

http://www.garagejournal.com/forum/showthread.php?t=232991 This thread is an example,,, personally the best safety factor is to have a single circuit to a machine, that's about as good as it gets.

 

[Norcal]

You do not need to turn them off and on daily and under load, stay simple and standard here and its 240V. If you have a complicated air system and a potential for leaks turn off ball valve at comp, its so rare to need to start it under load don't lose sleep and try to re invent all this.

Remember that the colour code for "220" is Brown for hot/live, blue for neutral, & green w/ a yellow stripe for ground/earth.

 

[ddawg16]

The 'big red kill switch' you speak of is called a E-Stop...or Emergency Stop.

They are typically put at the machine being used. In most cases, they are only used for machines where movement is taking place.....i.e., motors involved. You typically would not use one on a welder.

Disconnects are required when a machine or 'device' that is using the power is more than 25' from the supply source or out of site. Good example....AC unit outside your house....you have to have a local disconnect.

It's good to be safe...but adding disconnects and e-stops are not really going to have any substantial impact....especially if your not going to use the existing controls first.

 

[Norcal]

To have a "E-stop" it will take either a shunt trip circuit breaker or a contactor, neither are cheap. If the compressor has a magnetic starter, just wire a switch into the control circuit, even a simple light switch would do to shut off the compressor when not needed.
If done per above, the switch is not handling the load of the compressor.

 

[sberry]

I think I have some e stops in storage, saved them and never used one.

 

[theoldwizard1]

Id like to use a disconnect box with a manual knife switch so that I can kill the compressor and machinery overnight and in emergencies easily.

These are generically called "safety switches" as the contacts and all connection are inside of an approved box with the handle on the outside. Typically they have no fuse fuse/breaker.

Overkill, especially if the circuit breaker is in the same room.

Commercially they are required so that a person doing maintenance on the equipment can physically put a lock on the switch lever.

 

[justanengineer]

The 'big red kill switch' you speak of is called a E-Stop...or Emergency Stop.

It's good to be safe...but adding disconnects and e-stops are not really going to have any substantial impact....especially if your not going to use the existing controls first.

Im not talking about an E-stop mushroom, Im talking about a disconnect, tho admittedly my use of my father's shop as an example was terrible as he used a high (220) voltage E-stop mushroom as the shop disconnect (not the standard low-voltage control mushroom). I want a standard knife-switch disconnect w/4 or 6 breakered (not fused) circuits in the same box to use as the "subpanel." I dont want a "disconnect" thats just a smaller breaker box without the red mechanical switch on the side.

IME with industrial wiring, theres usually a machine E-stop mushroom on the control panel, a machine disconnect on the machine (for machine repair without disconnecting it), then a zone disconnect on a pole relatively close nearby (for installing/removing machines without killing the zone), and finallly the plant power disconnect/breaker located a long walk away. In an emergency where its closer or should the E-stop fail, the machine disconnect gets pulled quickly. Barring that, the zone gets killed which happens occasionally in our plant, whoever's nearby pulls the closest red handle rather than moving to hit the E-stop or machine disconnect. Safety first, red handles are easier to find than master breakers in the dark/smokey/panicked situations, even by kids and women, and also last longer than breakers when constantly being flipped. If Im working on something and I start yelling, I dont want her to have to deal with breakers or bs around, just pull the red switch to save my ***.

Just to give an example of why Id like to kill the power when Im not in the shop....The disconnect box on my Bridgeport shown below controls power to the mill via VFD, the worklight, the Moosehead neon sign above/behind it, and the 110 box below it. In the near future it will also power a DRO, another worklight, and eventually a power feed. Theres a lot going on and many failure points on this one machine alone between my wiring, cheap imported VFD electronics, and the 60 year old motor, so no, I dont trust it to stay powered full time nor does the VFD have an off switch of its own. Maybe if I had a detached garage Id be less concerned with this, but if my garage catches fire or has issues so does my attached house. This will be just one machine wired in, and admittedly not all will be this complicated, but Id rather be safe than sorry.

Admittedly, I could make a habit of going around each night and making sure Ive flipped every disconnect thereby killing power individually, but realistically Im lazy, forgetful, and paranoid. I could also use a standard breaker as a disconnect, but again, not sure thatd last too long.

 

[justanengineer]

Get lock out plates that fit over your new circuit breakers or just a big inline cut off switch that you can lock off.

Thanks for the input, I suspect I might need to use a combination of a single circuit disconnect and a standard breaker box subpanel.

Remember that the colour code for "220" is Brown for hot/live, blue for neutral, & green w/ a yellow stripe for ground/earth.

Thanks, got it. The question remains tho, do we really need that pesky ol ground? Jk.

These are generically called "safety switches" as the contacts and all connection are inside of an approved box with the handle on the outside. Typically they have no fuse fuse/breaker.

Overkill, especially if the circuit breaker is in the same room.

Commercially they are required so that a person doing maintenance on the equipment can physically put a lock on the switch lever.

Theyve been called disconnects everywhere Ive been, including the box stores. Most that I see/use also have several fuses inside so you can wire/protect multiple circuits and run multiple voltages, theyre really just a fuse box with a rugged on/off switch.

I was hoping we had a couple industrial or other electricians on this board that could tell me, "Yes, they make disconnects with breakers like you want. Here's a link...." Guess Im going to have to find a good electrical supply house.

 

[Grumpy365]

http://www.kele.com/motor-controls/abb-eot-series.aspx

http://grainger.com/product/SQUARE-D-Manual-Motor-Switch-1H402

I have used both of these for compressors etc.

 

[theoldwizard1]

I want a standard knife-switch disconnect w/4 or 6 breakered (not fused) circuits in the same box to use as the "subpanel."

I guess you skipped reading my post !

That is generically called a "safety switch". It generally does NOT have fuses or breakers inside.


You can achieve you goal, by installing an "appropriately" sized safety switch between your main panel and a sub panel with breakers whose circuit you want controlled by the switch.


A lot of money just to have a big handle to turn off a bunch of circuits. It is a nice visual indication of a circuit/machinery status from a distance, but so are pilot lights on the equipment.

 

[sberry]

Using breakers are fine, the equipment shouldn't be running when they are switched. At some point its likely you will get past this. Its just extra stuff.

 

[LS6 Tommy]

Breakers are NOT switching devices. They're circuit protection. You will wear them out turning them on & off all the time. If the motor is more than 2 hp or the breakers are more than 6' from the device you need a disconnect. For less than 2 hp you can just have a cord and a receptacle. Either way, you must have a motor controller & overload protection on each machine.


Tommy

 

[sberry]

If you have them on the machine you wont wear the breaker out? I have seen breakers used as switches for years, I dont know if they ever wore them out.

 

[sberry]

I was hoping we had a couple industrial or other electricians on this board that could tell me, "Yes, they make disconnects with breakers like you want. Here's a link...." Guess Im going to have to find a good electrical supply house.

We do have those guys here but they probably wont bother, they know when they are pushing uphill.

 

[pattenp]

Where are you getting this 6' rule from? NEC states the disconnect needs to be in sight of the equipment.

Breakers are NOT switching devices. They're circuit protection. You will wear them out turning them on & off all the time. If the motor is more than 2 hp or the breakers are more than 6' from the device you need a disconnect. For less than 2 hp you can just have a cord and a receptacle. Either way, you must have a motor controller & overload protection on each machine.


Tommy

 

[CoopVA]

Yes, they make disconnects with circuit breakers in them if you "want" one.

ANY Electrical Supply House can get them for you.

I prefer Square D...

In your situation though, it is not necessary to use them. You should run the main 2 phase feed from the house panel to a subpanel in the garage though, and then circuit from there. That is all that is required. You can use a disconnect switch before the subpanel if you really need to throw a switch when you exit the building...

 

[2ManyProjects]

I am getting ready to run a 220 line out to my garage, currently its 110V 20A outlets + lighting only. Ive gotten away with 110 only since buying the house by running 110-->220 VFDs but am getting ready to bring in the welders and a compressor that will need one, maybe two dedicated 220 circuits.

Notwithstanding the subsequent squabbling over disconnects and such, IF this is a detached garage (as I rather suspect it is, from some of the phrasing you used), then your plan will NOT work. Per code, you may have only ONE power feed into a given structure. So you will need to abandon your existing 120V circuit, and run ONE properly sized four-conductor feeder cable from the main panel (in your house) to a new sub-panel (in the garage/shop). That sub-panel, in turn will supply ALL the loads in the garage/shop.

Id like to use a disconnect box with a manual knife switch so that I can kill the compressor and machinery overnight and in emergencies easily.

You can do that. But it is neither here nor there with respect to what I said above. And really, I can think of all sorts of reasons to NOT kill ALL power to the shop/garage, even when it is unoccupied (alarm systems, security lighting, sump pumps, controls for such things as any HVAC equipment which might be installed now or later, automatic door openers, etc.). Put separate disconnects on any major loads you are especially worried about, if you like; but don't routinely interrupt the main feed to the building.

 

[mlcharlestonsc]

Only way to have lever disconect is to buy one, then install before distribution center.

This might help.

http://www.renovation-headquarters.com/images/electrical service cr.jpg

Modern distribution centers have main disconect in panel.

 

[sberry]

"I am, and ever will be, a white-socks, pocket-protector, nerdy engineer -- born under the second law of thermodynamics, steeped in the steam tables, in love with free-body diagrams, transformed by Laplace, and propelled by compressible flow."

The answer needs to take this in to consideration. Ha,,,, is this the place we are to use smileys