Overcurrent Protection for Flexible Cords 240.5

[philhurtgen]

Hey guys!

So, I have a question about section 240.5(A) that is puzzling me, and I can't seem to find any answers to it elsewhere online. I noticed that it says here that flexible cords and cables "shall be protected by an overcurrent device," and I'm wondering what would be an example of this, and what kind of overcurrent device it would be? It sounds strange to me to imagine installing some kind of separate breaker or something for a flexible cord, but I just work in residential. Perhaps they're talking about overcurrent protection that is usually built into equipment? 240.5(B) seems to generally allow most cords and cables that are part of an appliance to be considered protected, so I guess they're talking about some separate situation. Any help would be greatly appreciate. Thanks!

 

[tortuga]

Say you have a wiring project that is 'permitted' by 400.10 for a flexible cord,
For example my friends farm has a 7-1/2 HP single phase irrigation pump they use for a 4-5 months of the year to pump water out of a river. In the winter the river floods so the pump is removed and stored.
They run a 6 AWG extra hard service cord as the wiring method from the pump controller to the pump, the pump controller is the OCPD for the cord.

 

[philhurtgen]

Thanks! That's very helpful.

 

[kwired]

You have a branch circuit with a receptacle outlet.

Now you plug something in utilizing flexible cord - the overcurrent device for the branch circuit is all you have to protect the cord. If said device is sufficient to protect the cord then you are fine, if not you may need additional protection for the cord and there may be multiple ways you can do it. Some situations may have differences in what is allowed vs others as well, like your mentioned cord that is part of an appliance.

 

[RumRunner]

Hey guys!

So, I have a question about section 240.5(A) that is puzzling me, and I can't seem to find any answers to it elsewhere online. I noticed that it says here that flexible cords and cables "shall be protected by an overcurrent device," and I'm wondering what would be an example of this, and what kind of overcurrent device it would be? It sounds strange to me to imagine installing some kind of separate breaker or something for a flexible cord, but I just work in residential. Perhaps they're talking about overcurrent protection that is usually built into equipment? 240.5(B) seems to generally allow most cords and cables that are part of an appliance to be considered protected, so I guess they're talking about some separate situation. Any help would be greatly appreciate. Thanks!

Flexible cord protection is reflexive of your query about "separate situation" scenario.

This protection is common on European appliances or any power-consuming device such as string of decorative lights or small portable appliances etc.

The practice of cord protection is standard on apparatus that are used in countries that use RING CIRCUIT wiring system. . . notably the British Standard.
Australia and New Zealand do this also.
As you probably know the British Standard (ring circuit) differs from our North American radial style wiring standard. Their convenience outlet that we call receptacle or female plug are usually wired with wire gauge that has almost the equivalent of #10 AWG (2.5mm) and protected with 32 Amps fuse or circuit breaker.

Our North American mindset consider it a gross aberration if we plug a 5 Amp or smaller rated extension cord to a 32 Amp branch circuit. Although we often see an appliance with #18 cord.
In a case of overload, the cord in the British System would overheat or even burn up before the 32 Amp fuse blows.

Those factory built-in cords for small hand tools are limited to certain length. I haven't been able to track down the exact wording as mandated by UL however.
Perhaps others can chip-in on this.

You will notice that British male plugs are bigger than their North American counterpart.
That's because there is a small compartment in the male plug for a 10 Amp or smaller rated glass fuse in it.