I just picked up a new dust collector and it has a 20amp 3 wire 220v plug.
My new shop (I should post pics - there's some on arfcom) has 3 - 50amp 220 plugs.
I can't seem to get my electrician to swap breakers and plugs - even though we're in the middle of building a house and they're onsite regularly!
Do you guys see any issue with just making an adapter - or cutting off the 20amp plug and using the 3 wire 50amp male plug?
I've searched and found everything from - don't do it, to yeah not really an issue... but I figure there's a reason why no one makes an adapter...
I really need to get the new dust collector up and running for a project. What would you guys do?
DONT make an adapter.
And DONT cut off the 20a plug. You violate the listing doing this.
Instead, either swap the breaker and outlet or run a new circuit.
Running a new circuit is pretty basic and you can even get guidance on here on how to do it.
Like you said you can switch the breaker to 20amp and change the receptacle. Or run a new 20amp circuit.
It's pretty dangerous to hook a 20amp rated appliance to a 50 amp circuit. If the machine shorts there is nothing to protect more than 20 amps arriving at the machine....the internals of the machine is not rated for that. How fires start if there is a fault because the protection will not kick in until way above the machine rating. Best cause the wire melts in the machine and kills power to the machine however leaving an open pigtail plugged into a 50amp 220v circuit...worst case it all burns down. Neither case is an acceptable case
This isnt accurate.
People often confuse over-current with short circuit (happens many times on this forum).
Over-current is when current greater than the rating of the breaker is drawn. This is where the thermal portion of the breaker comes into play. The bi-metal strip in the breaker heats up and touches the trip bar.
Amp flowing during a short circuit, on the other hand, can be on the order of hundreds and even thousands of amps for split seconds depending on the voltage and type of service(tens of thousands of amps are possible in a short circuit on a 480v delta which can cause bus bars etc to melt and vaporize). This is called fault current. This is where the electromagnetic circuit in the breaker comes into play. The electromagnet attracts the armature and trips the breaker....
2 entirely different things.
You can have the same amount of short circuit fault current with a 20a breaker that you can have with a 50a breaker. The available short circuit fault current is all dependent on the size of the transformer feeding the service and the panel and breaker designs. Residential breakers are typically rated 10KAIC.......
Now in regards to OP, it is possible for one of the windings in the motor to fail and short circuit. a 20a breaker and a 50a breaker would clear this in the same amount of time.
On the other hand, a motor could start pulling more amps than the breaker is rated for say if the load the motor is connected to jambs.
But motors also have inherent in-rush current. So breakers for motor circuits are typically sized for only short circuit and ground fault protection. Separate over-current protection is provided in a motor starter or integral in the motor....
