Nema 4X panel board

[Aleman]

I want to make my own breaker box to be used as a sub panel. This will be a Nema 4X enclosure with din rail mounted breakers, using a buss for the supply side on the breakers. The breakers will be feeding 3 separate control panels. I looked at 240.3 on enclosures and 312.2 regarding damp locations. Am I missing anything, is there any NEC reason I can't do this?

 

[John120/240]

You want to fabricate your own NEMA 4X enclosure out of sheet metal ? Why not buy an off the shelf box and mount your

components inside it ?

 

[templdl]

I want to make my own breaker box to be used as a sub panel. This will be a Nema 4X enclosure with din rail mounted breakers, using a buss for the supply side on the breakers. The breakers will be feeding 3 separate control panels. I looked at 240.3 on enclosures and 312.2 regarding damp locations. Am I missing anything, is there any NEC reason I can't do this?

I would like to assume that by making your own breaker box that you will be purchasing a NEMA 4X box form an enclosure manufacturer and installing a DIN rail with the breakers in is. If so are you going to use UL489 breakers of UL1077 supplimentary protectors?
The reason that I ask is the breaker availability for DIN rail mounting. UL489 may be somewhat more difficult to get with provisions for DIN rail mounting. Since you overlooked including what the breaker ratings are that you intend to install it is a bit difficult to make any further suggestions.
If you are sourcing a NEMA 4X box I don't see and issues with what you are intending to do.

 

[Aleman]

Should have provided more info. Basically I need a small subpanel to feed 3 control panels outside. This is 460V 4 wire, 20 amps each. I will be buying a nema 4x enclosure and using din rail mount breakers that are UL listed. So, more or less a panelboard for circuit breakers but scaled down for my purpose. Cheaper too. My boss gets cheap sometimes and he didn't like the price of a pre made nema 4x panel board.

Here's another question....I need to add some controls for a 7-1/2hp dust collector, a starter and an estop and a couple of switches. I don't see any code reason I can't add this stuff into this panel. Am I missing something?

Thanks for the advice.

 

[jim dungar]

... din rail mount breakers that are UL listed. ....

Just be careful what breakers you choose. Simply saying UL Listed is not enough.

As templdl said, there are different breakers for different tasks. UL489 is the standard you want if the load wires will be branch circuits (e.g. they leave the panel). UL 1077 is for supplementary breakers which are used in conjunction with a branch protective device and , in the vast majority of situations, are in the same enclosure as the loads they serve.

Lets not forget the AIC rating of the devices. DIN rail mounted breakers have reasonable AIC ratings @ 240V, but their selection is limited at 480V.

 

[iceworm]

I want to make my own breaker box to be used as a sub panel. ...

Am I missing anything, is there any NEC reason I can't do this?

...I need to add some controls for a 7-1/2hp dust collector, a starter and an estop and a couple of switches. I don't see any code reason I can't add this stuff into this panel. ...

Assumption: You are not part of a NRTL panel shop (UL508A for example)

First: Does your state require listed equipment? If you get by that, then -

Your AHJ should consider this an industrial control panel. NEC 409 applies. If so, there are marking requirements - including an SCC rating.

There have been a few threads, where posters knowledgable about their AHJ, have said clearly, 'no panel build per NEC 409 would ever be allowed in their state' (parqaphrased).

IMO, nothing you can't do, just have to follow the code.

ice

 

[petersonra]

The devil is in the details as other posters have mentioned.

My guess is by the time you add all the stuff you are talking about into the thing you are looking at something not real cheap. It is likely that you will need to get it UL listed as an industrial control panel too. You can probably have a control panel shop make it for half what it will cost you to do it yourself.

Do you know what the available short circuit current will be at the new box?

Look closely at the interrupting rating of the DIN rail breakers. they will need to be UL489 breakers. Look close at the SCCR rating of the bus as well. You may well get a huge surprise there.

 

[Aleman]

The devil is in the details as other posters have mentioned.

My guess is by the time you add all the stuff you are talking about into the thing you are looking at something not real cheap. It is likely that you will need to get it UL listed as an industrial control panel too. You can probably have a control panel shop make it for half what it will cost you to do it yourself.

Do you know what the available short circuit current will be at the new box?

Look closely at the interrupting rating of the DIN rail breakers. they will need to be UL489 breakers. Look close at the SCCR rating of the bus as well. You may well get a huge surprise there.

Thanks for the suggestions and help. You guys are great. I was just at a UL seminar given by Siemens at a local electrical supply. UL is not a mandatory standard. Although I am sure many companies etc. require UL built panels, they are not mandatory per US law. The one thing we are not closely looking at is the SCCR. I honestly don't know what our supply is rated at. Otherwise we are building mostly to UL508A standards, but none of these panels will get listed. At least not right now.

That said, I need to throw together a quick and dirty but code panel to distribute power to 2 panels plus a new dust collector. I wanted to put a Nema4X panelboard out there but my boss nixed it so I have to make do. The other thing is we are interfacing with some poorly designed and built panels. The 2 existing panels are running off one feeder. The top lugs of the disco #1 have 2 sets of wires in them, one set feeds the 2nd panel. I intend to give each panel it's own feed.

 

[jim dungar]

The one thing we are not closely looking at is the SCCR. I honestly don't know what our supply is rated at.

So, you are willfully choosing to ignore NEC 110.9 and 110.10.

I am constantly amazed how many 'design and build' projects ignore these sections.

 

[Aleman]

So, you are willfully choosing to ignore NEC 110.9 and 110.10.

I am constantly amazed how many 'design and build' projects ignore these sections.

Sort of, yes. But we are using all UL listed parts when we build. I looked at the breakers we will be using and they are UL489. But I honestly don't know what our supply is rated at. I will try to find out. I realize I need to know this. I am trying to learn as much as I can so I can make sure the work I do is ok per the NEC. That's why I'm here.

 

[templdl]

Sort of, yes. But we are using all UL listed parts when we build. I looked at the breakers we will be using and they are UL489. But I honestly don't know what our supply is rated at. I will try to find out. I realize I need to know this. I am trying to learn as much as I can so I can make sure the work I do is ok per the NEC. That's why I'm here.

You may be on the right track as long as you stick with UL489 devices, applying them at an appropriate KAIC rating and knowing what the SCCR needs to be for the assembly.

 

[petersonra]

Thanks for the suggestions and help. You guys are great. I was just at a UL seminar given by Siemens at a local electrical supply. UL is not a mandatory standard. Although I am sure many companies etc. require UL built panels, they are not mandatory per US law. The one thing we are not closely looking at is the SCCR. I honestly don't know what our supply is rated at. Otherwise we are building mostly to UL508A standards, but none of these panels will get listed. At least not right now.

That said, I need to throw together a quick and dirty but code panel to distribute power to 2 panels plus a new dust collector. I wanted to put a Nema4X panelboard out there but my boss nixed it so I have to make do. The other thing is we are interfacing with some poorly designed and built panels. The 2 existing panels are running off one feeder. The top lugs of the disco #1 have 2 sets of wires in them, one set feeds the 2nd panel. I intend to give each panel it's own feed.

Properly done there is nothing wrong with feeding both panels off of the same feeder.

UL is not a mandatory standard but many places using stuff that is NRTL listed is.

Without knowing what the available short circuit current is at the point you intend to put this box you cannot properly select the components.

I would look very closely at the bus bar system you are planning to use. Many are not listed at all, only recognized.

 

[jim dungar]

But I honestly don't know what our supply is rated at. I will try to find out. I realize I need to know this.

Kind of a catch-22, when you are both the builder and the installer.

The panel builder does not need to know anything about the fault current at the source. They are the ones creating the SCCR of the equipment. Of course they may have specs they need to follow

The responsibility for correctly applying 110.9 and 110.10 falls entirely on the installer. This is why the NEC and UL require equipment to be labeled with an SCCR. And why the code now requires a label advising the available fault current.

 

[Aleman]

Properly done there is nothing wrong with feeding both panels off of the same feeder.


I would look very closely at the bus bar system you are planning to use. Many are not listed at all, only recognized.

The thing I don't like is the use of the disco as a bussbar for the next panel. The buss I will be using is built by the Eaton same as the breakers, UL listed.

 

[petersonra]

The thing I don't like is the use of the disco as a bussbar for the next panel.

This is a pretty common thing to do and there is nothing wrong with it as long as it is done in a proper fashion.

In the grand scheme of things it probably does not matter much if your box meets all the code requirements. There are untold millions of such things out there and very few if any have ever been a problem.

One of the things I have found is that in the quest to be "cheap" as you are suggesting your boss is doing in this case, it is not unusual for more money to be spent on something cobbled together that has all kinds of code issues to it than to just buy something that was correctly designed and built in the first place.

 

[templdl]

The thing I don't like is the use of the disco as a bussbar for the next panel. The buss I will be using is built by the Eaton same as the breakers, UL listed.

If the Eaton components that you refered to they must be reverse UR component listed then.

 

[petersonra]

If the Eaton components that you refered to they must be reverse UR component listed then.

if it says UR on it, that means it is not listed, only recognized. You can only use them in specified ways with listed components.

 

[jim dungar]

if it says UR on it, that means it is not listed, only recognized. You can only use them in specified ways with listed components.

Component Recognized means the device cannot stand on its own it needs something else. The something else is not always specified, and it may be another UR component.
For example:
Plug-in relay sockets need enclosures.
Plug-in relays need sockets.
DIN rail breaker bus bars need enclosures and breakers
Push-button contact blocks need operators.
Fluorescent sockets need fixtures.

 

[petersonra]

Component Recognized means the device cannot stand on its own it needs something else. The something else is not always specified, and it may be another UR component.
For example:
Plug-in relay sockets need enclosures.
Plug-in relays need sockets.
DIN rail breaker bus bars need enclosures and breakers
Push-button contact blocks need operators.
Fluorescent sockets need fixtures.

I was referring to his use of the UR part in conjunction with the listed CB he planned to use, although I can see that the way I worded the comment might have led you to believe it was more expansive. The point being that just because it is a listed Cb and the bus is a UR part does not mean he can use it with that particular listed CB.

 

[jim dungar]

The point being that just because it is a listed Cb and the bus is a UR part does not mean he can use it with that particular listed CB.

Absolutely.