Reality check: How many 50A 240VAC circuits?

[gotham]

I had a shop/barn built. I'll start a thread on it once I'm a little more moved in and comfortable. The building is about 30x40, with door on the south end (30') wall. Electrical panel is on north wall. All surface mount receptacles with conduit. I was going to run from the panel along the north wall and then along the west wall dropping down to receptacles periodically. Similarly, along the north wall the other way and along the east wall. At each location I'm planning on (2) 14-50R and (2) 5-20R receptacles on (4) separate breakers.

My question is: should I have (2) 240VAC and (2) 120VAC breakers for the north and west and then (4) more breakers for the east wall or (2) 240VAC and (2) 120V total. 240VAC beakers are <$35 and if I went with only (2) I would need to get another junction box and parts to make a three way connection which would eat up some of the savings. (4) 240VAC 50A circuits seems like a crazy number but it's not much more $.

Use is general hobby shop. Mostly just me but maybe some friends working as well. Welders, machine tools, etc.

Thanks.

 

[wyliesdiesels]

why do you need 2x 50a receptacles in the same spot?

 

[PhantomEB]

I had 3 in my last garage and it was only a 24x24! One in each corner but one.

But then again it also had 27 110 plugs too, even my beer fridge was on its own 15amp breaker!

 

[wyliesdiesels]

I can understand spread out but in the same spot?

 

[mm08822]

Sounds like you want to hang a lot of dead $ on the walls.

Back up and ask yourself how these would be used and how likely at the same time.
What do you need the 50s for?

What if there was just 1 on each 30' wall and 1-2 on each 40' wall. All on the same circuit? Would hardship is there?

 

[mike93lx]

What ifs are the most expensive shop upgrades...

If you can't come up with a reason to have a 14-50 (something basically no shop equipment needs), I bet it's a waste of money

I bet you can reasonably estimate where you need to plug in a welder or a large stationary machine, and if that changes, modify wiring at that point

 

[Steve from Socal]

In my 19x26' garage in California I had 6 -240 breakers for machines. Five were 50 amp one 30 amp. That was in addition to the house loads. I would have only had one or two active, compressor and milling machine or lathe? The welder and plasma used plugs the others were hard wired. The machines that were hard wired has fused disconnects at the machines.

Motor loads over 3 HP should be hard wired or use devices rated for the motor load not a 14-50

 

[Norcal]

My shop has a 50A welder circuit that has been unused for years, & a couple of 60A Pin & Sleeve receptacles attached to interlocked switches for a MillerMatic 251, & a 50A circuit for a 5 HP air compressor attached to one of the few single phase combination starters I have ever seen, most are 3Ø. Most of the other 240V circuits are 20A.

 

[gotham]

Thanks for the feedback.

What is the preferred 50A 240V receptacle if not 14-50R? I've built/modified a few CNC machines that typically have some 120V loads usually run by a transformer which could be replaced by the neutral. Perhaps this is "what if" thinking.

Big loads I currently own are a milling machine 40A (in storage), air compressor, and TIG welder 43A. A number of other saws, grinders etc. My thinking on paired receptacles was being able to choose which breaker to plug into at a given location. If the mill is on breaker "A" plug the welder into breaker "B". If TIG welder is on breaker "A" plug 2nd welder into breaker "B". Again "what if" thinking.

I'll hardwire mill and compressor.

For receptacles maybe I'll do one circuit on the N and W walls and one on the E wall. No real cost savings to having a single circuit due to the cost of making connections in 6 awg wire.

 

[u2slow]

Just another strategy... I have no machines that need/use #6 so I have a small subpanel on those heavy runs instead. Then I have whatever smaller circuits I need local to the sub-panel. Most of my 240V circuits are 20A.

 

[yatg]

A reason to have grouped 6-50r's are if you have a welding/cutting station and you don't (I sure don't) want to unplug/plug every time to switch machines.
A small subpanel and multiple circuits is going to be cleaner than joining multiple #6/#8 wires.

 

[dcg9381]

What is the preferred 50A 240V receptacle if not 14-50R? I've built/modified a few CNC machines that typically have some 120V loads usually run by a transformer which could be replaced by the neutral. Perhaps this is "what if" thinking.

That's my preferred one and I use it all over the place. Sometimes I put them on 30A circuits (with a label) - depends on what it's going to power.

With a shop that big, I'd probably drop a sub-panel across and then branch from that. Cost of 90A aluminum (for the sub panel) is going to be less than 6ga copper, so it might actually "save" money and make things easier to branch on the other side.

 

[Steve from Socal]

On machines that use a transformer for control voltage I have used a neutral to supply power. My small lathe 10EE is single phase 240 with 120 control. The stuff like welders don't require neutrals so 6-50's not 14-50's. Motor loads should be hard wired not plugged in with either a 6-50 or 14-50. Regarding plugs, perhaps an extension cord and a few outlets would be a better choice? My shop has plugs about every 30', it is a big space, with a 25' extension cord I can have a welder near any location.

 

[wyliesdiesels]

Thanks for the feedback.

What is the preferred 50A 240V receptacle if not 14-50R? I've built/modified a few CNC machines that typically have some 120V loads usually run by a transformer which could be replaced by the neutral. Perhaps this is "what if" thinking.

Big loads I currently own are a milling machine 40A (in storage), air compressor, and TIG welder 43A. A number of other saws, grinders etc. My thinking on paired receptacles was being able to choose which breaker to plug into at a given location. If the mill is on breaker "A" plug the welder into breaker "B". If TIG welder is on breaker "A" plug 2nd welder into breaker "B". Again "what if" thinking.

I'll hardwire mill and compressor.

For receptacles maybe I'll do one circuit on the N and W walls and one on the E wall. No real cost savings to having a single circuit due to the cost of making connections in 6 awg wire.

you may need additional overcurrent protection depending on the load.

 

[gotham]

I appreciate all the feedback. I have up to a 1" EMT bender and getting rid of the neutral for a 6-50R vs a 14-50R makes the conduit fill better not to mention saving cost. I'm going to focus on getting conduit and some junction boxes running along the tops of the walls. I ordered a 8x6x4 box with knockouts to test but I might go a bit bigger. After that I'll do a few drops to get started on what I know I want and build from there.

 

[yatg]

you may need additional overcurrent protection depending on the load.

nonsense.

 

[wyliesdiesels]

nonsense.

doubt that is NRTL listed.

 

[LopezBart]

I can certainly see having multiple welder outlets in the same place to avoid switching plugs; I'd connect them to the same circuit, however. I'd also include a 240/125 outlet as well. If you need to use a welder elsewhere in the shop, a proper 50A extension cord (which would also facilitate welding outside on something that doesn't fit in the shop right now) would help... in fact, a (commercial or homemade) spider box to go on the end of that cord would make a lot of sense as well.

 

[mm08822]

doubt that is NRTL listed.

It is actually.......as an RV splitter cord. I'm sure that makes you feel safer.

 

[sparky 1971]

I can't speak for anyone else, but I would definitely feel safer knowing that I can run my chopsaw, miter saw, and shop vac at the same time. There is much less of a chance of tripping due to not having to walk across the shop to reset a breaker.

 

[LopezBart]

I can't speak for anyone else, but I would definitely feel safer knowing that I can run my chopsaw, miter saw, and shop vac at the same time. There is much less of a chance of tripping due to not having to walk across the shop to reset a breaker.

I find it difficult to use a chopsaw, miter saw, and shop vac at the same time, but then, I'm just a amateur .

 

[sparky 1971]

I find it difficult to use a chopsaw, miter saw, and shop vac at the same time, but then, I'm just a amateur .

It takes practice pulling the triggers, especially with the left hand, and the shop vac can just be left on with the hose laying in a strategic place.

 

[TurnipTruck]

I put one 50a receptacle on each 16’ wall in my metal shop. The mirror image duplicate wood shop in the opposite corner has the same setup. I never use the 50a recepts above the benches, so the single on the back wall feeds the Tig or the Mig or the sander or the plasma. I should have tripled the receptacles on the back wall and/or run a larger conduit in the floor and had two separate 50a circuits for the hardwired stick welder and an additional receptacle under the table.

 

[mm08822]

I can't speak for anyone else, but I would definitely feel safer knowing that I can run my chopsaw, miter saw, and shop vac at the same time. There is much less of a chance of tripping due to not having to walk across the shop to reset a breaker.

try a walker with wheels.

 

[mikedodge]

I've always made do with one 50A outlet. I only mainly use it for welding or powder coating and always need an extension anyway because of how short the equipment cables are.

 

[gotham]

I like the idea of a 20' or 30' extension cord to increase the flexibility of the space. It looks like the premade ones are the same or less expensive than just the cord. I assume I should go with 6 gauge / 3 conductor for the 6-50R. Is there such a thing as (2) 6 gauge wires with a #10 ground in a flexible cord?

 

[u2slow]

I assume I should go with 6 gauge / 3 conductor for the 6-50R. Is there such a thing as (2) 6 gauge wires with a #10 ground in a flexible cord?

Use the gauge cord appropriate for the machine (or largest machine) you will run on it. Just like there are #16, 14, 12, and 10 extension cords for the usual 5-15R receptacle.

Appliance cord whips (range/dryer) are the only thing I can find with mixed wire sizes within. One source for used cable is to ask at a local marina. The molded ends often burn up from corrosion, and most folks just buy a new one.

 

[whateg01]

I find it difficult to use a chopsaw, miter saw, and shop vac at the same time, but then, I'm just a amateur .

How about bandsaw, miter saw, and shop vac? My shop vac runs with the miter saw and the bandsaw can run semi-unattended.

 

[LopezBart]

I like the idea of a 20' or 30' extension cord to increase the flexibility of the space. It looks like the premade ones are the same or less expensive than just the cord. I assume I should go with 6 gauge / 3 conductor for the 6-50R. Is there such a thing as (2) 6 gauge wires with a #10 ground in a flexible cord?

Consider using Type W portable power cable; it has a higher amp rating. For example, 4 conductor 8GA type 4 is about $5/foot and is rated for 65 amps.

 

[gotham]

Consider using Type W portable power cable; it has a higher amp rating. For example, 4 conductor 8GA type 4 is about $5/foot and is rated for 65 amps.

Interesting. I've never heard of Type W. SEOOW 6/3 $4.25 (600V 55A listed capacity). 8/3 Type W $4.43 (2000V 65A listed capacity.

 

[mm08822]

Consider using Type W portable power cable; it has a higher amp rating. For example, 4 conductor 8GA type 4 is about $5/foot and is rated for 65 amps.

Looks like a good contender to SOOW.