Temporary Panel

[Rentalguy]

Does an outdoor temporary distribution panel require a main breaker?

 

[George Stolz]

It depends. Can you describe the equipment in question, and the situation?

 

[Rentalguy]

Temporary Panel

The panel is a 200A quad box feeder panel (NEMA 3R)for the special event business. It would be powered by a 30 or 50kW generator feed with 2/0 type w cable. Inside the panel is 24, 20A QC circuit breakers. So you would have 8 3 phase recepticles for output.

 

[George Stolz]

IMO, it sounds as though this panelboard would require a main breaker.

 

[yanici]

I agree with George. Also, when we put out our panels we needed driven ground rods even though we had full sized EGC's.

 

[Rentalguy]

The manufacturer's claim that the NEC does not require a main breaker for the panel.

 

[yanici]

I wonder if the manufacturer expects you to rent a disconnect switch along with the panel.

 

[Rentalguy]

I guess they don't care about the disconnect. They just claim that the NEC does not require that panel to have a main breaker or disconnect switch.

 

[Dennis Alwon]

We just had a thread similar to this on temporary power outlets. I am really not sure that this would fit but if this unit is specifically design for the situation and is not considered a panel, etc then it may fall under some other category---

What is a quad feed panel? What do you mean?

 

[George Stolz]

I would say that 408.36(A) exception 1, could be applied to this situation. Since the feeder to the panelboard must be protected in accordance with it's ampacity, then this section would not require a main breaker.

However, as I see it 225.31 would still require a main disconnect, assuming the panelboard isn't laying in the dirt.

I don't see anything in Article 525 or 590 relieving us from the main disconnect, perhaps someone can explain the manufacturer's position. I am also unsure what a "quad feed feeder panel" is.

 

[mdshunk]

Isn't the feeder overcurrent protection at the genset? This panel is more like a spider box that we use on the jobsite, from the sounds of it. They sure don't have main breakers.

 

[yanici]

They make "Spider Boxes" that are supplied with, I've seen up to a 50 amp twist lock "inlet receptacle". I don't know if these boxes have mains or not. These boxes have limited versatility compared to a panel.

The big rental place around here has all cam-lock connected stuff to mix and match. So, it's easy to patch a 200 amp switch to a 200 amp panel.

 

[Rentalguy]

This is a temporary panel built specifically for temporary outside use. The description "Quad Box" feeder panel is the panel has 208VAC, 3 phase outlets that feed "Quad Box" strings, which are 3 phase cables with 3- 120VAC, 20A Edison outlet every 10' or 20' or 30'. The panel may be a 6 position, 8 position or 10 position panel. These panels are built specifically for the special event business.

 

[Dennis Alwon]

Does the panel say it is suitable for service equipment???

 

[dbuckley]

As someone on the receiving end of these sorts of temporary supplies, I'd sure like the distro to have a main switch. That way when the supply loses it's neutral I can try and contain the scale of the disaster...

Its also a good idea for the main switch to be a main breaker, as then the distro is protected from the lack of upstream overcurrent protection, which is common in these circumstances. You arrive at the site, and the house or site electrician tails you in to a 400A supply, despite the fact the cable from the tails to the distro and the distro itself is only rated at 200A. You smile sweetly, thank the electrician nicely for giving you power, and just get on with it.

 

[Rentalguy]

Dennis, what do you mean by "service" equipment?

 

[Dennis Alwon]

Dennis, what do you mean by "service" equipment?

I was assuming this temp. pole is considered service equipment since it is being fed from the generator. I am be wrong here tho.

I am also thinking that this panel is on a separate structure as temp. power poles often are . If this is the case, then art. 225.33 might be pertinent and you would need a max. of 6 discos. However, if the pole is service equipment and is manufactured as a unit with breakers and all and is listed as suitable for service equipment then I would think you would not need a main breaker. I may not be visualizing this setup correctly.

 

[dbuckley]

To help in visualising, what I think the OP is talking about is something like this:

Note this sorry specimen appears not to have a disconnect, despite there being a hole for where it should be...

 

[Pierre C Belarge]

Is this a listed piece of equipment? If so, how is it listed?

 

[dbuckley]

I assume you are joking. Thats as listed as I am, but never-the-less, thats how power gets distributed in temporary settings.

This picture turned up, which shows a couple of distros in use in the UK, for quite a decent size event, see if you can spot something scary in this one

(err - how do I make that attached image appear inline?)