225.40

[paul32]

Can someone explain the point of 225.40?

When the feeder OCPD is not readily accessible (hmm, but overcurrent devices are supposed to be readily accessible...well, maybe an exception), then branch circuit OCPD shall be installed on the load side (of what? the feeder? of course it is, by definition), be readily accessible (umm, of course), and shall be a lower ampere rating than the feeder. (Well, higher makes no sense, and why not the same?).

And more humor, 225.40 is one of the exceptions to the readily accessible requirements of 240.24, but 225.40 says it has to be readily accessible.

Happy Thanksgiving everyone.

 

[finhead]

I was following you up to the last sentence where you said: "but 225.40 says that it has to be readily accessible." I think you meant another Section because 225.40 does not require the OCPD to be readily accessible.

 

[dcspector]

OCPD.....readily accesible NEC 240.24(A)

 

[Bob NH]

Paul32 "Can someone explain the point of 225.40?"

225.40 Access to Overcurrent Protective Devices. When a feeder overcurrent device is not readily accessible, then branch circuit overcurrent devices shall be installed on the load side, shall be mounted in a readily accessible location, and shall be a lower ampere rating than the feeder.

Now let's parse it:
When a feeder overcurrent device is not readily accessible,
(only applies in this case for which all of the following requirements apply)

1) then branch circuit overcurrent devices shall be installed on the load side,
2) shall be mounted in a readily accessible location,
3) and shall be a lower ampere rating than the feeder.

When the feeder overcurrent protective device IS readily accessible, then none of the subsequent conditions are required by 225.40. They MAY be required by other sections of the Code.

 

[charlie b]

. . . then branch circuit OCPD shall be installed on the load side (of what? the feeder? of course it is, by definition). . . .

What this means to me is that you now have to install branch circuit OCP devices. It isn't a question of putting them on the load side or the line side or the far side of the moon. It's a question of whether you need to install them at all. I suppose this would come into play if you were to want to tap a feeder to create branch circuits, but wanted to use the tap rules so that you could leave out the branch circuit OCPDs.

Once you see that interpretation, the next two statements (about being readily accessible and having lower rating than the feeder) start to make more sense.

 

[George Stolz]

Can someone explain the point of 225.40?

No, but I can bluff with the best of them.

When the feeder OCPD is not readily accessible (hmm, but overcurrent devices are supposed to be readily accessible...well, maybe an exception)...

Here's another way to look at it: Are your neighbor's OCPDs required to be readily accessible to you? Or, are the POCO fuses in the transformer required to be accessible to you, so you can shut your service off?

Most people would say "no" to both questions. Does your lack of access mean that the neighbor's OCPDs aren't readily accessible as far as the NEC is concerned? I think that is the point of the section.

...then branch circuit OCPD shall be installed on the load side (of what? the feeder? of course it is, by definition)...

I think that is just a case of redundant wording, you're right. But it sure is easy to read, though, isn't it?

...and shall be a lower ampere rating than the feeder. (Well, higher makes no sense, and why not the same?)

I think in the event of an overload, they're looking to create some selective coordination, and try to cause an OCPD that is readily accessible at the remote structure to trip. It might be a convenience issue (as opposed to a safety issue), but not an excessive one, IMO.

The safety imperative might be cut glass from breaking and entering to reset breakers, you never know.