Disconnect on 120V, 20A Industrial Control Panel

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JimMacD

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Hello,
I am designing a control panel for a couple PLCs that has a single incoming power source (120VAC, 20A Feed). What is an appropriate means of disconnecting this and meeting the NEC requirements?

Thank you

-Jim M
 
Article 409 does not seem to specify disconnects for situations without Motors, or single-phase applications. Table 409.3 points to Article 670, which has this statement:


"(670.4 B) Disconnecting Means. A machine shall be considered
as an individual unit and therefore shall be provided with
disconnecting means. The disconnecting means shall be
permitted to be supplied by branch circuits protected by
either fuses or circuit breakers. The disconnecting means
shall not be required to incorporate overcurrent protection."
 
JimMacD said:
Hello,
I am designing a control panel for a couple PLCs that has a single incoming power source (120VAC, 20A Feed). What is an appropriate means of disconnecting this and meeting the NEC requirements?

Thank you

-Jim M
Click to expand...

The NEC does not specify what an appropriate disconnecting means is.

Conceivably a plug and cord would be adequate.

I don't mean to be picking on you, but the phrase "I am designing a control panel" suggests you should know this kind of stuff already, or be under the supervision and tutelage of someone who does.

I always get nervous when people ask this type of question, especially a newish poster.
 
petersonra said:
The NEC does not specify what an appropriate disconnecting means is.

Conceivably a plug and cord would be adequate.

I don't mean to be picking on you, but the phrase "I am designing a control panel" suggests you should know this kind of stuff already, or be under the supervision and tutelage of someone who does.

I always get nervous when people ask this type of question, especially a newish poster.
Click to expand...

Precisely why I came to this forum, Bob. Just trying to understand and learn the right way of interpreting the code from those who are experts in the field.
 
JimMacD said:
Precisely why I came to this forum, Bob. Just trying to understand and learn the right way of interpreting the code from those who are experts in the field.
Click to expand...

This is a good place to learn, no doubt about it.

UL508a is a good standard for control panels. The NEC really does not cover control panels other than to just touch on them.
 
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