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220V table saw and wiring

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Forum topic by spooky1 posted 08-25-2015 10:26 AM 1663 views 1 time favorited 24 replies Add to Favorites Watch
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spooky1

6 posts in 1238 days


08-25-2015 10:26 AM

I just moved my entire shop (military guy so I am used to it). I am in a pickle, I have a Jet tablesaw which has a three prong plug, it reads 20A 250V

on my new wall it has a female receptacle which reads 50A 125/250V

so my question is how do i make this work without burning down my new shop


24 replies so far

View johnstoneb's profile

johnstoneb

2147 posts in 1639 days


#1 posted 08-25-2015 10:43 AM

Make a pigtail adaptor from one to the other.

-- Bruce, Boise, ID

View Marv's profile

Marv

21 posts in 669 days


#2 posted 08-25-2015 11:13 AM

Depends how big the breaker is, I too have a Jet cab saw and it’s on a 20 amp circuit. And I would change the outlet. And thank you for your service.

-- I have never asked someone to do something I haven't or won't do.

View OggieOglethorpe's profile

OggieOglethorpe

1213 posts in 1577 days


#3 posted 08-25-2015 11:29 AM

I’d go with the first suggestion of the pigtail… Easy to do with a prewired range plug and a receptacle.

Why?

You have a 50A circuit, and right now, a 20A saw. The 50A circuit can handle anything you pick up in the future requiring up to 50A. Why hamstring it? You never know when you would like to connect a heater or A/C, welder, large compressor, welder, or some other power hungry tool.

View Fred Hargis's profile

Fred Hargis

3949 posts in 1960 days


#4 posted 08-25-2015 11:42 AM

Yep, the pigtail will be easy to do and the more immediate (quicker) solution.

-- Our village hasn't lost it's idiot, he was elected to congress.

View HokieKen's profile

HokieKen

1807 posts in 605 days


#5 posted 08-25-2015 11:56 AM

If it were me, I’d leave the receptacle/breaker alone. No problems there since the circuit has higher capacity than the saw pulls. The pigtail’s a good idea. But it’ll save some $ to just put a new plug on the cord coming from the saw. Lowe’s lists both the plug and the receptacle for 15$. So it costs you $15 to change the plug or $30 (+ the cable) to make a pigtail (I’m sure you can find them cheaper online if you’re not in a hurry). If that’s the outlet you’ll be using for your time in that house, there’s no need to be able to plug it into another type receptacle. I’d just change the plug out and put that one up. If your next shop has a 20A circuit, just swap the plugs back out. Of course, you know you’re next shop is BOUND to have a 30A circuit :-)

And, like Marv said, Thank You for your service!

-- Kenny, SW VA, Go Hokies!!!

View Clarkie's profile

Clarkie

380 posts in 1308 days


#6 posted 08-25-2015 12:02 PM

That outlet is for either a welder or a stove, why mess with it at all. Call an electrician and put in a 220 outlet, why Rube Goldberg it? There may be the ability also to change your saw back to 110 also, save this outlet for the big stuff, you may have or get a welder in the future.

View bonesbr549's profile

bonesbr549

1176 posts in 2534 days


#7 posted 08-25-2015 12:56 PM

Technically you could just change the plug. However, I would not and here’s why. You have 20A rated wiring going to your saw. Your circuit is 50A. This means if anything goes wrong and it’s starts overheating, it will burn up before tripping that 50A breaker. Could mean fire and you die. Do it right, and either run another 20A circuit to your main, or, put in a sub panel, that could support your existing need and the saw.

-- Sooner or later Liberals run out of other people's money.

View OggieOglethorpe's profile

OggieOglethorpe

1213 posts in 1577 days


#8 posted 08-25-2015 01:03 PM

Why do so many assume a breaker protects the load where a plug and receptacle is involved?

Do you rewire rooms when you add lamps or TV’s? Golly, you’re really risking things if you’re only using a 1 amp lamp on a 20A circuit!

Portable devices that have plugs include some sort of current protection. His saw has a breaker, probably right on the motor, other times in the switch mechanism, that protects the saw.

It makes perfect sense to size a circuit to a hardwired device. This is not one of those cases…

View jiggles's profile

jiggles

48 posts in 744 days


#9 posted 08-25-2015 01:13 PM

I’m with Bones….put in a sub panel. That way you can add more 120/240 lines using the correct size breakers to protect you and your loved ones. Never scrimp on quality of tools or electrical power.

-- Jiggles, Huntsville (Prison City), Texas

View HokieKen's profile

HokieKen

1807 posts in 605 days


#10 posted 08-25-2015 01:59 PM



Why do so many assume a breaker protects the load where a plug and receptacle is involved?

Do you rewire rooms when you add lamps or TV s? Golly, you re really risking things if you re only using a 1 amp lamp on a 20A circuit!

Portable devices that have plugs include some sort of current protection. His saw has a breaker, probably right on the motor, other times in the switch mechanism, that protects the saw.

It makes perfect sense to size a circuit to a hardwired device. This is not one of those cases…

- OggieOglethorpe

Yep. There is no reason to downsize your circuit. If that were necessary, we would never be able to use any tools that draw less than 15 amps. A sub-panel is a great idea but is costly and entirely unnecessary. The saw has a breaker or fuse either on the motor or the switch, like Oggie said. If somehow your saw has been rebuilt and doesn’t have one, put a fuse in the line no matter what circuit/receptacle you’re using.

What’s being suggested with changing the plug or using a pig-tail is in no way “rigging” anything up. It is entirely safe and is a proper way to do it. There’s nothing wrong with a sub-panel or downgrading the circuit but there’s no need for it either.

-- Kenny, SW VA, Go Hokies!!!

View WhyMe's profile

WhyMe

617 posts in 1027 days


#11 posted 08-25-2015 02:26 PM

That 50A outlet should be changed to a 6-50. The 10-50 is an old style range outlet that is ungrounded, that is it uses the neutral as a ground and the neutral is bonded in the range frame. This is why the outlet says 125/250V. If that circuit comes direct from the main service panel then using the neutral as a ground is not a real issue because the neutrals and grounds are bonded at the main panel, but if that outlet is off a sub-panel then the neutral should be moved to the ground bar in the sub-panel if using it as a straight 250V outlet. So there can be a little more to it than just making up a pigtail if you want the circuit to be NEC compliant. You can add at sub-panel on the circuit but it will be 250V only, no 125V because you don’t have the 4th wire to get 125V.

View Fred Hargis's profile

Fred Hargis

3949 posts in 1960 days


#12 posted 08-25-2015 02:31 PM


Why do so many assume a breaker protects the load where a plug and receptacle is involved?

Do you rewire rooms when you add lamps or TV s? Golly, you re really risking things if you re only using a 1 amp lamp on a 20A circuit!

Portable devices that have plugs include some sort of current protection. His saw has a breaker, probably right on the motor, other times in the switch mechanism, that protects the saw.

It makes perfect sense to size a circuit to a hardwired device. This is not one of those cases…

- OggieOglethorpe

Yep. There is no reason to downsize your circuit. If that were necessary, we would never be able to use any tools that draw less than 15 amps. A sub-panel is a great idea but is costly and entirely unnecessary. The saw has a breaker or fuse either on the motor or the switch, like Oggie said. If somehow your saw has been rebuilt and doesn t have one, put a fuse in the line no matter what circuit/receptacle you re using.

What s being suggested with changing the plug or using a pig-tail is in no way “rigging” anything up. It is entirely safe and is a proper way to do it. There s nothing wrong with a sub-panel or downgrading the circuit but there s no need for it either.

- HokieKen

Yep…what they said^^^^^^

-- Our village hasn't lost it's idiot, he was elected to congress.

View GerryB's profile

GerryB

69 posts in 2049 days


#13 posted 08-25-2015 03:46 PM

First, IF you’re renting or in a government lease, Ask for permission to change it. Get that in writing! (DAMHIKT) I’d be asking someone at work to take a look & advise me on the best way to do it. This assumes your name is not based on your job. If that is the case call an electrician. Remember, what you install (like a sub box) immediately becomes a permanent part of the structure, and cannot be removed later.
R/Gerry USCG (Ret)

-- The pursuit of excellence is gratifying and healthy. The pursuit of perfection is frustrating, neurotic, and a terrible waste of time. Edwin Bliss

View bonesbr549's profile

bonesbr549

1176 posts in 2534 days


#14 posted 08-25-2015 03:47 PM


Why do so many assume a breaker protects the load where a plug and receptacle is involved?

Do you rewire rooms when you add lamps or TV s? Golly, you re really risking things if you re only using a 1 amp lamp on a 20A circuit!

Portable devices that have plugs include some sort of current protection. His saw has a breaker, probably right on the motor, other times in the switch mechanism, that protects the saw.

It makes perfect sense to size a circuit to a hardwired device. This is not one of those cases…

- OggieOglethorpe

I guess a tool has never shorted out causing an overload and a fire. My first house had a federal pacific panel and d breakers. I remember learning what happens when a breaker does not trip on a short.

If the circuit was a 30 am and the wiring was 20, I’d say thats pretty close. 50A is one heck of a jump. Hey if he wants to risk so be it. It’s safer to at least match wire,plug,receptacle, and breaker.

Further, you go violating codes and you burn your house down, you give your insurance carrier room to do the old negligence thing on you. It’s just not worth it. Just saying.

Get permission do it right, and you are covered.

-- Sooner or later Liberals run out of other people's money.

View HokieKen's profile

HokieKen

1807 posts in 605 days


#15 posted 08-25-2015 04:16 PM

Actually, most lamps have 18 ga. wire which is only NEC compliant for up to 6A. The wire from the panel has to be sized for the breaker it comes off of. The wire coming from the fixture/tool only has to be sized for the current it draws, not the current available from the service.

BUT, bones has a point about the wire size and homeowners insurance. In order to be NEC compliant, anything that taps into a 50A circuit has to have 12ga or larger wire. So, in order to be fully compliant, you’d need to either swap out the breaker to a 20 or 30A breaker or rewire your saw with 12ga wire (assuming your saw currently has 14 ga which is good for up to 30A). Swapping the breaker is the cheaper option.

-- Kenny, SW VA, Go Hokies!!!

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