220 electrical question

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mtnboomr

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But that also means it's fine to run his saw on his 50amp plug right? Because that will more than handle the saws amp draw.
Yes, he could. But running the saw on the 50-amp breaker runs a higher chance of the breaker not tripping during an overload or short circuit in the motor. This can cause the saw to catch fire, or even the motor to explode.
 

mtnboomr

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The best idea would be mounting a small (like 2 or 4 breakers) breaker panel in the garage. Feed it with the 50A circuit. Mount one 50A beaker, and one 30A breaker in the box. Then add 50A and 30A receptacles.
Remember, this is only a stop-gap solution. It WILL NOT run more than one machine at a time without tripping.
 

Ahall

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overcurrent protection
This is how I think about it.
The breaker in the wall panel is sized to prevent overheating of the wires at the maximum amperage they are rated for. You can pull up to that many amps through the wires without issue.

When you plug in a device rated for lower amperage, you need to provide overcurrent protection at that device - a fuse, a breaker, heaters in a motor starter, etc.

Table saws are easy enough to bind on heavy rip cuts and the locked rotor current of a single-phase capacitor start motor can quickly fry the capacitors and windings. The concern about protecting the saw from electrical damage is valid, and I write with the wisdom that only comes with experience. If you ever pay someone to rewind a motor with a goofy frame, you will appreciate the value of good overcurrent protection.

Having rebuild, rewired and repaired many wood working machines, something jumped out at me. The first post indicated 17 amps at 220 V, that's roughly 5 hp, which is typical of a cabinet saw, like the Powermatic 66 or Delta Unisaw. Classic light professional class saws.

All bets are off on a used saw that bubba messed with, but from the factory most equipment in the 5hp range had a motor starting system that was more sophisticated than your average light switch.
There is a very good chance the saw has some kind of overcurrent device already engineered into the motor starting device on the saw. Use the breaker to protect the wires to the plug. Incorporate a second device at the machine to protect the machine. This has been the normal approach in light professional woodworking machines for well over 50 years.

Before spending money on additional overcurrent protection post some photos of the electrical gear on the saw. You may already have the overcurrent device your worried about needing.

Also, if you decided to change the saw from 110 to 220V, by swapping some wires at the motor, good chance there are other things in the motor starter that need to be addressed as well.
 
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Rez Exelon

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1730342662637.jpeg
 

dennishoddy

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Rez Exelon

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That's an RV outlet that is already wired. 230V 50 amp, 230V 30 amp outlets as well as a 20 amp GFCI outlet for 120V with breakers to protect them.
Installed one just like that last year for our RV, running 4ga THHN solid wire in conduit from the main.
Could that be something workable for the use case here? The thing I can't see in the description is the input type. It seems to have the plug types OP wants, but I can't tell if it's wire into the existing outlet.

I've looked at CEP "temporary" power boxes for my house. They used to be $180 and would hook into a dryer outlet and work as a breakout to multiple plugs. Should have bought one back in the day because they're like $350 now. But in that case it's just sub dividing the circuit into 120v outlets. Considering that I could use more 120's in my garage rather than the dryer hookup that's spare (since the dryer was remodeled inside the house) it's a cool solution, but not cool enough to make me pay the current cost.
 

dennishoddy

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Could that be something workable for the use case here? The thing I can't see in the description is the input type. It seems to have the plug types OP wants, but I can't tell if it's wire into the existing outlet.

I've looked at CEP "temporary" power boxes for my house. They used to be $180 and would hook into a dryer outlet and work as a breakout to multiple plugs. Should have bought one back in the day because they're like $350 now. But in that case it's just sub dividing the circuit into 120v outlets. Considering that I could use more 120's in my garage rather than the dryer hookup that's spare (since the dryer was remodeled inside the house) it's a cool solution, but not cool enough to make me pay the current cost.
That was a different animal from what pic you posted.
What your describing is sometimes used during construction jobs for temporary power, not for any kind of permanent installation or extra circuits past that project.
Anytime plug-ins are used there is always a chance the outlet used for power could get some corrosion and create a little resistance in ohms. It takes very little resistance to create heat that is incredible.
Ohms law with the numbers plugged in can tell one how much
 

montesa

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Could that be something workable for the use case here? The thing I can't see in the description is the input type. It seems to have the plug types OP wants, but I can't tell if it's wire into the existing outlet.

I've looked at CEP "temporary" power boxes for my house. They used to be $180 and would hook into a dryer outlet and work as a breakout to multiple plugs. Should have bought one back in the day because they're like $350 now. But in that case it's just sub dividing the circuit into 120v outlets. Considering that I could use more 120's in my garage rather than the dryer hookup that's spare (since the dryer was remodeled inside the house) it's a cool solution, but not cool enough to make me pay the current cost.
The standard thing to do would be to put in a sub panel and then run outlets out of that. It's not expensive if you do it yourself.
 

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