Are Over Current Protection Devices Meant to Protect Equipment?

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But-a-mear-splice

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Like the title says, I am wondering if over current protection devices are meant to protect equipment?


Such as: Kitchen appliances, washer/dryer, HV/AC equipment, counter top appliances, TV's, radios, power tools, welders, spa pump/heater, pool pumps/heaters, PV equipment, RV's, etc. . .


My gut tells me, if they are attached by plug or whip to the structure's wiring system they are also part of that system and need the protection afforded the electrical system itself.


I know (or at least I think I know) that they are in place to protect, panels, wiring, receptacles, luminares, and such.
 
Nope. Overcurrent devices have only one function: to protect the conductors that run from the device to the load and back to the panel. The way such devices are typically installed, they can serve the secondary function of safely de-energizing the load so that maintenance can be performed. But that function could be instead performed with a local, non-fused, disconnect switch.

Welcome to the forum.
 
david luchini said:
See 240.3
Click to expand...

So, yes. Overcurrent protection devices are meant to protect all of the equipment listed in Table 240.3.

Which, for the most part look to be hard wired equipment, or equipment that is typically hardwired?

And, no. Not equipment such as, counter top appliances and other equipment that are typically plugged in?
 
But-a-mear-splice said:
So, yes. Overcurrent protection devices are meant to protect all of the equipment listed in Table 240.3.

Which, for the most part look to be hard wired equipment, or equipment that is typically hardwired?

And, no. Not equipment such as, counter top appliances and other equipment that are typically plugged in?
Click to expand...

Well, OK, but what is the OCPD protecting the equipment from? Overcurrent, yes, but how would such a thing happen? From the OCPD's point of view, how can it tell a hardwired piece of equipment from a cord connected one?

I submit that OCPD is there (mostly, anyway) to protect the conductors and prevent fires.
 
It doesn't matter where the overcurrent comes from, the OCPD just has to stop it! If it happens to protect either hard-wired or plugged-in equipment, that's a bonus!
 
It might depend on if you are just looking at the NEC or beyond that. A widgit machine usually doesn't have any ocpd inside of it so I assume there are product/listing standards that assume a certain ocpd in the branch circuit to protect the internal wiring and lower the available fault current.
 
PaulMmn said:
It doesn't matter where the overcurrent comes from, the OCPD just has to stop it! If it happens to protect either hard-wired or plugged-in equipment, that's a bonus!
Click to expand...

I would venture to say that since the OCPD is sized to protect the circuit conductors,

and,

Those circuits generally operate efficiently without nuisance tripping,

The likelihood that the BCOCPD will protect the equipment,(Without some other type of supplementary overcurrent protection built into the equipment itself) would be slim to none.


JAP>
 
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