Installing a 220v outlet in the garage

[billmanweh]

I have an electrician coming out Friday to put a 220v outlet in the garage, next to the breaker

He asked what type of receptacle I wanted, but I don't have a clue

Initially, I want the outlet for a 2hp belt grinder, but I haven't wired a plug onto the motor. But I was also hoping to use the outlet for a small welder in the future.

How do I know what type of plug and receptacle I need? And is there any chance of the grinder would use the same plug that I put on the grinder?

 

[Cruzan80]

My guess is the grinder and the welder will not use the same amp plug. This is probably what he is asking. Otherwise, he is asking curved (locking) or flat bladed plugs.

 

[Dick in Wisconsin]

Do you have the 2hp belt grinder? If so, the electrician should be able to look that over and decide what you need.

One option is for him to install a box big enough for two receptacles; one for the belt sander and one for a future welder. I know this has been discussed before, there might be a problem with two different outlets on the same 220/240volt circuit.

How much extra room do you have in the panel? Enough room for two 220/240volt circuits? If so, then two circuits each with its own outlet. When you get the welder, wire in the proper receptacle for the welder.

Not enough room for two circuits? Then probably a sub-panel off the main that will branch off to separate circuits.

Keep us posted.

 

[JJThrasher]

You'll find Nema 6-50 on many welders. Assuming the motor on the grinder has its own overload protection you could just have the one outlet and swap as needed.

 

[billmanweh]

Assuming the motor on the grinder has its own overload protection you could just have the one outlet and swap as needed.

I'll double check that, but is that enough protection? Or is there a danger using the motor on a 50a circuit?

 

[wyliesdiesels]

Unless the welder is small, it wont use the same plug as the sander.

 

[sberry]

Modern welders come with 15A 120v or 50A 250 if they come factory cord and plug. The 240v can use a smaller breaker, 30A. But the plugs are not the same as other types of machines where the style is a current limiter.
There are some types of machines with additional overcurrent that can be used on larger circuits, some depend on the circuit breaker for their own internal protection. If it comes with 20A plug then that's the breaker should be on it. This is a good place to stretch a little or learn to wire a simple circuit. I like a welder circuit for welders although I do share the wire on my hoist with a welder outlet as the breaker requirements are the same.

 

[billmanweh]

So, essentially, I'm not going to be able to use the grinder and a welder on the same outlet/circuit? Not at the same time, of course. But not at all?

 

[Jackpod]

Size the circuit to the needs of the larger device. In other words if the welder is 50 amps and the grinder is 20 amps, install a 50 amp circuit. It is then possible to make a pigtail with the same matching 50 amp connector on one end, then put a 20 amp connector on the other that matches the grinder. Two important factors here. 1) The breaker protects the wiring, not the plugged in device 2) current (amps) is drawn, so a device that is a 20 amp device can be attached to a 50 amp circuit (same as a 1amp device can be plugged into a 20 amp circuit).

 

[Norcal]

Size the circuit to the needs of the larger device. In other words if the welder is 50 amps and the grinder is 20 amps, install a 50 amp circuit. It is then possible to make a pigtail with the same matching 50 amp connector on one end, then put a 20 amp connector on the other that matches the grinder. Two important factors here. 1) The breaker protects the wiring, not the plugged in device 2) current (amps) is drawn, so a device that is a 20 amp device can be attached to a 50 amp circuit (same as a 1amp device can be plugged into a 20 amp circuit).

But you cannot put a 20A device on a 50A circuit.

 

[Jackpod]

You sure can, can't you plug a small sander or a soldering iron into a 20a outlet? as long as the voltage is correct IE 120 or 220. THe circuit breakers are there to protect the wiring to the endpoint device, not the device itself. Current is drawn, voltage is the force. so on a 20 amp outlet the device can pull up to 20 Amp, on a 15 amp circuit you can pull up to 15 amps. it doesn't mean that the 20 amps is going to be fed to the device. the only time it matters is with the phase you can't run a 220 single phase device on a 3 phase circuit vice versa. In regards to your statement you CAN plug a 20 amp device into a 50 amp circuit but you CAN NOT plug a 50 Amp device into a 20 Amp circuit. You will find with twist locks that there are Nema 5L20's 5L30's 6L20's 6L30 etc, The 5 is for 120 volt, the 6 is for 220 volt that is the rating of the connector and since they are pinned differently is for safety reasons so you don't plug a 50A device into a 20A circuit. Why they make adapters or aka pigtails. The rule of thumb is consider the breaker the source and the device the destination, as long as the source has a larger current capacity than the next connection point towards the destination you are fine and within code. The connector that is installed on the device is rated above maximum current draw and each range is different so you don't overload the wiring. Adapt down, not up

 

[Cruzan80]

Can, yes. Should, probably not.

 

[Jackpod]

Let me clarify, a 20 amp L6-20 (220V 20A) will not physically fit into a L6-30 (220V 30A) but if you get an adapter that is a female L6-20 on one end and a male L6-30 on the other it is perfectly viable as the endpoint device will never exceed the current rating of the L6-20 and the L6-30 doesn't care

 

[Jackpod]

I work in large datacenters and it is done daily for capacity reason. All of the overhead drops are a minimum of 30 amps (some 120 some 220), not all racks require 30 amps and the price difference between a 20 amp power distribution unit and a 30 amp is huge, not to mention equipment changes in the racks frequently. it is more efficient to adapt down instead of calling the electrician every time a piece of hardware with different power requirements is changed out

 

[Jackpod]

In the case of the OP. If he has a 50 amp receptacle installed. then either makes or has made a pigtail with a 50 amp male connector on one end and a 20 amp female connector on the other, when he wants to use the 20 amp device he plugs in the pigtail and plugs the 20 amp device into it, there is no way the 50 amp device could be plugged in with out removing the pigtail. In this case it would be impossible to overload any of the lower amperage devices

 

[sberry]

There is a difference for dedicated circuit hooked to equipment like a data center. JACK, this is not the same as plugging a 1 amp to a 20. Stuff comes with a 15 plug is designed to go to 20, stuff designed for 20 is not designed for 50. The wire to it and internals of the machine not for it. I related this above.

 

[rnscustom]

Check the plugs on the new 110/220 welders that are out there , put an outlet for that , then put that style plug on your sander , when you buy a welder buy accordingly . Like said the wire and outlet/breaker determine the largest amp you can draw not the lowest . Only thing is you can't rely on the breaker to save your motor which you shouldn't anyway .

 

[rnscustom]

A welder that has 110/220 is not likely to draw 50 amps . The newer units are inverter types . If he's thinking of using a 50amp welder on the same circuit he should just do a dedicated for that

 

[sberry]

The MVP machines have special plug on the 240 side to let them run on 50A. They have 14 cords which is limited to 30 except for the adapter. A 240 only small mig machine comes with a 12 cord and 50 end, has additional protection after the switch for the thermal and internals.

 

[Jackpod]

The OP said there wasn't room in the panel for 2 dedicated circuits. In what I suggested the components rated for 20A would never be exposed to a device rated for 50. The point I was trying to make is if the proper wire gauge and receptacle are rated for the highest draw, anything lower doesn't matter. Current is drawn, not pushed. the only difference between dedicated and distributed circuits is dedicated circuit is just that dedicated, there is no second outlet around the corner for someone to plug something else in and change the calculated draw. At the panel they are identical

 

[sberry]

We go over the nature of plug and cord design about once a week. There may need to be a sticky, I get tired of writing it and my explanations become convoluted.

 

[rnscustom]

My tig 200 is a 30a plug ,

 

[sberry]

Did it come factory?
They certainly could. do that especially if they want to cheapen the cord and swiches, some internal parts. It would be limited to a 30A circuit.

 

[rnscustom]

Can he just add a reset switch or breaker for required amp at the sander to protect it . Most all my machines have resets

 

[rnscustom]

I use the same extension cord for my tig and Hobart 190 both factoryp

 

[sberry]

Can he just add a reset switch or breaker for required amp at the sander to protect it . Most all my machines have resets

Yes provided the cord is heavy enough for the short circuit protection of the breaker its plugged in to. It would have to be 12 for 50A. 14 for 30

 

[Jackpod]

*sigh*

 

[rnscustom]

That's actually what I have , a 50a for my electric heater and stick welder and I made an extension cord with a 50a plug and a 30a outlet for the tig and Hobart mig .

 

[rnscustom]

12 for 50a and 14 for 30a is way too small ?? More like 6 and 8 ??

 

[sberry]

That is its short circuit rating. 8 for 100A and 6 for 200. The wire or cord is sized and protected by the max applied load, the wire then needs to be adequate to fault the breaker.
If you look at a 210 class welder at 240 volt. They actually allow a 14 with a 30, the machine comes with a 12 cord, it's bigger than the macine requires but is sized so it can be connected to 50A welder circuit.

 

[sberry]

In general circuits with multi receptacles the breaker protects the wire from thermal, service entrance wires too but on many dedicated it's simply an off on switch and for short circuit.
Fixture wires are like this. An Edison base is up to 200 watts, or a fixture lists the max lamp. A wire smaller than 16 would serve the load, the breaker doesn't protect it from thermal, what does is that it's only got 100 watt lamp connected.
Wire must be heavy enough to trip a 20A breaker in the event of a fault. Christmas lights are a good example. Back in the day had greedy lamps and heavy wire, now tiny wire with a 2A fuse allows them to be on 20.

 

[sberry]

Air conditioning wire, motor circuits often have big breaker, small wire. The motor won't overload the wire, needs breaker with enough headroom it doesnt trip on starts.

 

[wyliesdiesels]

12 for 50a and 14 for 30a is way too small ?? More like 6 and 8 ??

If youre talking wire size for welders, there is special rules that allow downsizing of wire based on duty cycle of the welder.

So you could very well put #10 or even #12 on a 50a breaker. The welder doesnt draw 50a for more than a short time period and thus the wire wont overheat.

 

[Matt Matt]

I didn't read all the posts, but what is the FLA of the sander? Put in a circuit 2.5 times larger and a four prong plug. The sander will need a new plug the welder will need the same plug.

The problem I have with the situation is my welder needs 50 A and most 2 hp Sanders need about 15-20 A. But, you're really pushing the spectrum from both sides. Welders are in a special electrical situation based on their duty cycle under electrical code . So, your choices are a 6-50 with 40 or 50 A or a 14-50 with 40 or 50 A Circuit . All four options come with quite a bit of difference in price, but none of them are really wrong.

Now, all your options double if you want to go with twist lock plug at double the price.

 

[wyliesdiesels]

I didn't read all the posts, but what is the FLA of the sander? Put in a circuit 2.5 times larger and a four prong plug. The sander will need a new plug the welder will need the same plug.

The problem I have with the situation is my welder needs 50 A and most 2 hp Sanders need about 15-20 A. But, you're really pushing the spectrum from both sides. Welders are in a special electrical situation based on their duty cycle under electrical code . So, your choices are a 6-50 with 40 or 50 A or a 14-50 with 40 or 50 A Circuit . All four options come with quite a bit of difference in price, but none of them are really wrong.

Now, all your options double if you want to go with twist lock plug at double the price.

unless i missed something, no need for a 4-wire plug as both are 240v...

 

[Matt Matt]

unless i missed something, no need for a 4-wire plug as both are 240v...

The op said he wanted it for a grinder as well. I was starting to think this was the all in one large tool plug. Some grinders have smaller 120v motors for power feed and for coolant pump's. I was just trying to cover all the bases. But, you are correct. A 6-50, 40 amp circuit is probably all he needs.

 

[sberry]

Again, if this is a cord and plug sander it cant go on 40 or 50A, its limited to the plug that came on it.
Depending on the welder he may only need a 30.

 

[mike93lx]

this all seems more complicated than needed. I don't think i would be putting in a dedicated 240v circuit for a 2hp machine. can the motor be wired for 120v? if so, just do that and wait until you actually get a welder.

even if it can't for the cost of the electrician, it is probably cheaper to put a 120v motor on the grinder.

 

[sberry]

By changing a plug and breaker we may be bypassing one of the most important safety designs with the equipment. After all why bother with all these specific plugs, why not just put everything 240 on a 50 and call it a day?
Obviously,,,, or maybe not there is more to it than a rudimentary thought that the plug is just there to make sure it gets enough electric as it needs. That is part of it, 1 part to insure its heavy enough and doesn't overheat but the other 1/2 of it is to insure its plugged in to a current limiter that the machine is designed for. So it will short circuit before it burns the wire in half in the event of a fault.

 

[sberry]

This is why we don't put in 50A recepts and simply put 6 wire with multiple recepts like we do with generals on 120V, its simply that not everything is designed to be on a big breaker.
Lots of stuff, my pressure washer for example. Many of the internal wires are a size larger than pones go on 120v models even though they carry 1/2 the current. The only additional thermal is on the burner blower motor, it has different leads than its cousin, the little one has 16, the big one 14, all the control wires are 14 in it. Comes with 30A plug. All its parts are 240V, blower motor, transformer, all with wire way heavier than they need to run them.