Cord and plug lathe

[Krusscher]

I've been asked to install a small 240v 3ph lathe into a existing 30 amp twist lock plug on a 20 amp circuit that is shared by 2 other lathes that are cord and plug. I'm wondering if this is an acceptable disconnecting means for this equipment. In the past I would put a disconnect above the receptacle so I never have to unplug anything live but I'm not sure if that would be over kill. Also for bringing the rubber cord into the panel there is a 3/4 hole drilled in the machine, can I just put a 4 square over that hole and run the cord with a cord grip into that or does it have to be some sort of special junction? the reason i ask is because the other lathes have a junction box like you would see on a motor where the wire comes in.

 

[hbiss]

I question whether you can get away with another machine on that 20A circuit. Add the numbers up and see.

No. I wouldn't waste my time with a disconnect and a receptacle. A receptacle alone is fine.

Without seeing the machine and where the cord is supposed to go, I have no idea what you are talking about. With most lathes and milling machines I am familiar with the power cord comes into the switch. Could you post a picture of it and one of the other lathes you are talking about?

-Hal

 

[mtnelect]

I upgraded 480-volt sorting tables and forklift chargers in a produce warehouse from plug connected to fusible lockable disconnects. Didn't like the fact that 480-volt 3 phase was that close to human hands.

 

[jap]

I've been asked to install a small 240v 3ph lathe into a existing 30 amp twist lock plug on a 20 amp circuit that is shared by 2 other lathes that are cord and plug. I'm wondering if this is an acceptable disconnecting means for this equipment. In the past I would put a disconnect above the receptacle so I never have to unplug anything live but I'm not sure if that would be over kill. Also for bringing the rubber cord into the panel there is a 3/4 hole drilled in the machine, can I just put a 4 square over that hole and run the cord with a cord grip into that or does it have to be some sort of special junction? the reason i ask is because the other lathes have a junction box like you would see on a motor where the wire comes in.

9 times out of 10 you're not going to be opening the disconnect under a load anyway.

Most times a 4 square is placed over a hole in the side of a machine simply to redirect the cord straight down and not have the 90d bend in the cord going into the machine.

As far as whether the circuit is large enough for 3 machines, that would depend on if they use all 3 at the same time, and, if so, if it can handle the FLA plus the inrush of all starting at random times.

JAP>