Adding table saw to welding circuit?

[GreenNV]

I have a 240v welding circuit that is flush mounted to my workshop wall. I just purchased a 3hp 220v Powermatic table saw. I would like to add the table saw to the same circuit.

Since I will not/cannot be using the welder & table saw simultaneously, I would like to know if this setup meets code or must each be on a dedicated line.

If legal, I would like to know the setup for installation. The welding circuit uses 10 gauge wire and is 30 amps.

Thanks.

 

[DIC]

You could put the same plug on each machine and plug either one in the outlet

 

[G_P]

You could put the same plug on each machine and plug either one in the outlet

Exactly what I would do.

 

[Bib Overalls]

Yes, change out the plug. Or, if you need an extension cable make one up with the 50 amp plug and the receptacle that matches the plug on the saw. #10 stranded wire would be a good choice.

 

[GreenNV]

You could put the same plug on each machine and plug either one in the outlet

Outstanding suggestion; something I never thought of due to the size of the welding socket. I was ready to go an purchase a sub panel and branch two circuits from it. Your idea saved me a lot of time and effort. Thanks.

 

[GreenNV]

The saw comes with about 5 feet of wire and no plug. I"ll just replace the wire to the motor with a longer section and purchase the same plug that is on the welder.

 

[mooseeater19]

What is the FLA (full load amps) of the tablesaw. That is the first question that needs to be answered.

 

[GreenNV]

What is the FLA (full load amps) of the tablesaw. That is the first question that needs to be answered.

The table saw load is 21 amps, same as the welder, so I should be good to go since the circuit is 30 amps.

 

[zkling]

What is the FLA (full load amps) of the tablesaw. That is the first question that needs to be answered.

Should be around 20 or less. A nema 6-50P/R should work fine, which IIRC has a motor rating of 3hp.

 

[Jackfre]

I just did this at the house. I went to uniform plugs for the plasma, welder, Unisaw. It was a kinda temporary set-up for the house remodel that got trimmed up to a permanent set-up.

 

[JakeKohl]

There's nothing wrong with adding another 220V outlet and leaving them both plugged in on the same circuit. For instance, you can easily have five 20 amp outlets on one 20 amp circuit.

If you had them hard-wired (i.e. not a outlet / plug setup) the circuit would need to be sized for the full combined load..otherwise, with outlets, you are fine.

 

[srmofo]

All my welders, air compressor, and table saw have the 6-50p. Works great

 

[AZ Pete]

I use to unplug the clothes drier to plug my saw in.....that was in our last house. We don't have the laundry in the garage in this one, thankfully.

 

[TAMPAGT07]

There's nothing wrong with adding another 220V outlet and leaving them both plugged in on the same circuit. For instance, you can easily have five 20 amp outlets on one 20 amp circuit.

You would not be able to run them at the same time though, correct? If each were drawing 20 amps...

 

[Hooked]

I use the L1430P plugs/receptacles for my PowerMatic and compressor. Is this a good/acceptable arrangement or should I switch over to the 6-50p?

 

[Dr.Jones]

It is not legal to use a 50 amp plug on wire that is only rated at 30 amps. Some day someone may come along and plug something in that does use 50 amps and when they do, the wire that is only rated at 30 amps will over heat and the protective coating will crack or melt off and catch things on fire. If the wire is THHN and ran in EMT as the insulation melts one if the "hot" wires could come into contact with the grounded conduit. A bigger problem is if its ran in romex, then it will melt in the wall. If you have a good electrical panel like a Square D brand the breaker may trip before anything really bad happens. The cord ends and there matching outlets are meant to be added safety. It all has purpose even if it may not seem that way. I am a union electrician and have seen this happen before.

 

[srmofo]

It is not legal to use a 50 amp plug on wire that is only rated at 30 amps. Some day someone may come along and plug something in that does use 50 amps and when they do, the wire that is only rated at 30 amps will over heat and the protective coating will crack or melt off and catch things on fire. If the wire is THHN and ran in EMT as the insulation melts one if the "hot" wires could come into contact with the grounded conduit. A bigger problem is if its ran in romex, then it will melt in the wall. If you have a good electrical panel like a Square D brand the breaker may trip before anything really bad happens. The cord ends and there matching outlets are meant to be added safety. It all has purpose even if it may not seem that way. I am a union electrician and have seen this happen before.

If you have a 30 amp breaker on it, how is it going to pull more than 30 amps before it trips?

You are obviously not use to wiring circuits for welders either, as many of the "hobby" type units come with a 6-50P installed from the factory with instructions stating a 30 amp breaker as well as 10/3 romex. IIRC my diversion 165 stated a 35 amp breaker with 10/3.

 

[GreenNV]

It is not legal to use a 50 amp plug on wire that is only rated at 30 amps. Some day someone may come along and plug something in that does use 50 amps and when they do, the wire that is only rated at 30 amps will over heat and the protective coating will crack or melt off and catch things on fire. If the wire is THHN and ran in EMT as the insulation melts one if the "hot" wires could come into contact with the grounded conduit. A bigger problem is if its ran in romex, then it will melt in the wall. If you have a good electrical panel like a Square D brand the breaker may trip before anything really bad happens. The cord ends and there matching outlets are meant to be added safety. It all has purpose even if it may not seem that way. I am a union electrician and have seen this happen before.

Thanks for the clarification.

When I purchased the house, the workshop had a 30 amp receptacle for a 220v kiln. I replaced the receptacle to match the plug of the welder, a NEMA 6-50 R. To meet code based on your response, I should have changed the plug on the welder to match the existing 30 amp receptacle since the welder only had a draw of 21 amps.

The cheapest solution for me is to purchase a NEMA 6-50 P plug for the table saw. Since I am the only one in the workshop, I would know the equipment power needs. However, when I sell the house, I will replace the receptacle back to 30 amps to prevent the scenario you stated.

I do not know electrical code but it makes sense that there are different plug/receptacles for different power needs.

 

[sberry]

You can put a 50A recept on a 12 powered by a 50.

a 30 amp breaker as well as 10/3 romex. IIRC my diversion 165 stated a 35 amp breaker with 10/3

I hant read the diversion but my guess is you may recall incorrectly, I bet its a 14 wire with 35A breaker, Its rated to use a 50 provided the wire is 12 or better. I would have no real problem with another convenience outlet provided breaker and wire match similar to a general use circuit.

 

[JakeKohl]

You would not be able to run them at the same time though, correct? If each were drawing 20 amps...

no. The breaker would have a fit and protect the wiring. The same is true of practically all of the outlets in your house. If you plugged in 15Amp devices to all of the outlets and turned them all on the breaker(s) would pop to protect the wiring.

 

[sberry]

Jake, good explanations.There are good answers to specific questions on the forums and I see some good work on grounding but we could use some more about the "nature" of overcurrent protection. I would have never delved in and thought about it all if not for the forum system.

I don't know all the specifics and get confused when there are more than 4 wires, I really don't know anything about electric but am an installer.

Applied load, applied combined load etc. Some cases duty cycle may be applied. An interesting little tidbit may be the 200A wire welder. Falls at the top of some nema code stuff,, anywayit comes with a 12 cord but can be fed with a 14. I think the Diversion is the same and in the manual it lists 35 breaker, they assume the installer knows all this. It should be clarified in lay language since these are target marketed,,, that while the spec sheet says what it says it is provided with a 12 cord allowing it to be plugged to common 50A welding circuits. In theory you can connect 2 of these to a 50 , a 12 from each to the breaker.

Provided you drew load from only one at a time could use a machine twice as large such as a 225 stick, when that load went off could run the other wire the same. You could plug them, 2 small machines on to the same wire provided it was an 8.

 

[sberry]

My neighbor has a hobby garage, he is a master electrician. Got a fuse box in the garage. Has a 10 romex stapled to the studs to the range side of the box with 50A and to the feed thru has a 10 to a one armed bandit for an air comp. Runs about 2 rods a year and the air on occasion.

In theory you cant have 2 plug in points on an undersized over breakered wire, 1 may be ok.

 

[sberry]

We see a lot of worry to tears about voltage drop in intermittent use. An example is,, the contractor built it in a week from 150 ft of 12 cord, now the home owner is going to dodder off doing installs and he "might slide by" with a fist full of calculations between the 20A or 15A load on the 10 wire the guy got for the job?

I really got to wonder where guys learn the math to something like this. Got a 15# drop across a whip on an air tool and got to pipe up the main a couple sizes where the loss was already down to .4 a 100 ft. Factor in the fact that the garage is 24x36, anyone think how big the pipe to the reg needs to be?

 

[Dr.Jones]

If you have a 30 amp breaker on it, how is it going to pull more than 30 amps before it trips?

You are obviously not use to wiring circuits for welders either, as many of the "hobby" type units come with a 6-50P installed from the factory with instructions stating a 30 amp breaker as well as 10/3 romex. IIRC my diversion 165 stated a 35 amp breaker with 10/3.

You are correct, I have never wired up a "hobby unit." To be honest i dont think I've ever seen one. Most of what i do is 50 amp or higher usually 3 phase.

Just as a good work practice know one i work with ever puts on a outlet or cord end that's not of an equal rating as the equipment being used. Thank you for the lesson.