keef47
New member
- Location
- Rock Falls,Il
does the Nec have a regulation about having a disconnect before the plug can be connected or disconnected and should it be at what distance.
Installing 480v plugs for Machines
- Thread starter keef47
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Volta
Senior Member
- Location
- Columbus, Ohio
Keef, welcome to the forum!
I am not aware of any such requirement in normal locations.
There are some location where it could be needed, though. Look at 501.105(B)(6)(1), and that counts for all voltages.
I am not aware of any such requirement in normal locations.
There are some location where it could be needed, though. Look at 501.105(B)(6)(1), and that counts for all voltages.
Girl Engineer
Member
- Location
- Portland, OR
I would usually look at 630.13 and 630.33, as we mostly use a disconnect with a plug for welders. If you are talking about motors, look at 430.102(B), which requires the disconnecting means to be in sight from the motor location, with a couple of exceptions. Per the exception, if the motors are being fed from a MCC with a hasp for lockout, you can use the MCC bucket as the disconnecting means. Definitely do not use a plug if you go this way.
Plugs should not be thought of as the disconnecting means, because even household motors are required to have a switch or CB. We do use plugs at our site for motors, but procedures and practice require that the line is de-energized and even locked out before the plug is disconnected. If you think this might be an issue, leave out the plug and just use a lockable disconnect. There is no reason to jeopardize someone?s safety for convenience. Arc flash should be avoided, not designed in.
If you do end up putting in a plug, Make sure you are using cable that is rated for the location - no SOOW. Also make sure that it is twist-lock. Always put the disconnect close to the plug, so it is easy to switch before unplugging. Welding outlets are great for this, just make sure what you are doing falls under the UL. Make it easy to do the right thing, and never underestimate user error.
Plugs should not be thought of as the disconnecting means, because even household motors are required to have a switch or CB. We do use plugs at our site for motors, but procedures and practice require that the line is de-energized and even locked out before the plug is disconnected. If you think this might be an issue, leave out the plug and just use a lockable disconnect. There is no reason to jeopardize someone?s safety for convenience. Arc flash should be avoided, not designed in.
If you do end up putting in a plug, Make sure you are using cable that is rated for the location - no SOOW. Also make sure that it is twist-lock. Always put the disconnect close to the plug, so it is easy to switch before unplugging. Welding outlets are great for this, just make sure what you are doing falls under the UL. Make it easy to do the right thing, and never underestimate user error.
Girl Engineer
Member
- Location
- Portland, OR
I forgot to mention that most welding outlets have an interlock that does not allow you to unplug without turning off the switch and de-energizing the plug. That is very important.
TxEngr
Senior Member
- Location
- North Florida
I was checking and couldn?t find an NEC requirement around having a disconnect before a plug. However, you could look to NFPA-70E for some guidance here since disconnecting an energized plug would be considered an arc flash hazard requiring appropriate PPE probably not worn by those disconnecting things. That?s why the interlocked welding plug was developed. There are also plug systems manufactured by Meltric that are rated as disconnects if you are plugging in equipment since they are rated for load break.
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