Panel Location to Transformer

[killer76]

I have an application were the designer has located the transformer(45kva)directly in front of the loadcenter

could someone tell me if this is a code or safety issue

I have been told in the past that you may not block the entrance to any loadcenter / panelboard within 3 foot area

thanks
Robert

 

[charlie b]

Re: Panel Location to Transformer

If by "front," you mean the side from which you operate the breakers, and from which you can remove a panel to do work inside the load center, then you were told the right thing. NEC Article 110.26 would require a minimum of 3 feet of clear space in front of the load center. It must be the width of the load center, or 30 inches, whichever is more. Nothing can be installed or stored in that space.

 

[augie47]

Re: Panel Location to Transformer

charlie b, may I add ?

3) Height of Working Space The work space shall be clear and extend from the grade, floor, or platform to the height required by 110.26(E). Within the height requirements of this section, other equipment that is associated with the electrical installation and is located above or below the electrical equipment shall be permitted to extend not more than 150 mm (6 in.) beyond the front of the electrical equipment.

Many years ago, we had a internationally know company ship in pre-fab units made as you described (If I read correctly). Bit of a battle (the ole "we use them all over the world and nobody turns them down" story) but they redesigned to meet code,

 

[petersonra]

Re: Panel Location to Transformer

the key would seem to be whether the equipment is "likely" to require hot work.

perhaps the argument is that hot work is unlikely to be required.

110.26(A)
Working space for equipment operating at 600 volts, nominal, or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized shall comply...

 

[charlie b]

Re: Panel Location to Transformer

Quite true, Bob. That word "likely" is key to the requirement. But I would wager that there isn't an AHJ in the country (OK, that there are not more than 3) who would accept the notion that a panelboard (or "load center," to use the phrase from this question) is unlikely to require maintenance while energized.

Another key word, by the way, is "require." One could argue (and I would guess that some have tried) that the panel does not "require" maintenance while energized. So even if I choose to do maintenance while energized, it hadn't been "required." My earlier wager would cover this argument as well.

 

[macmikeman]

Re: Panel Location to Transformer

Killer, I have an extra dolly I would be glad to rent out to you for a reasonable large sum . It would be most useful in relocating the transformer out of the way.

 

[realolman]

Re: Panel Location to Transformer

I guess I must lead a sheltered life. Why in the world would you put a transformer in front of a breaker panel?

[ September 10, 2005, 08:46 AM: Message edited by: realolman ]

 

[iwire]

Re: Panel Location to Transformer

Originally posted by realolman:
I guess I must lead a sheltered life. Why in the world would you put a transformer in front of a breaker panel?

Way back (1982 ) that was how I was taught, locate a 480Y/277 panel right next to a 208Y/120 panel place the transformer under both.

This keeps all the wire runs to the transformer short.

I must admit as long as the transformer is 75 KVA or less it is not bad servicing the panels, you have a nice work bench to place your stuff on.

But times change we just don't do it like that anymore

[ September 10, 2005, 08:58 AM: Message edited by: iwire ]

 

[George Stolz]

Re: Panel Location to Transformer

Originally posted by charlie b:
Quite true, Bob. That word "likely" is key to the requirement. But I would wager that there isn't an AHJ in the country (OK, that there are not more than 3) who would accept the notion that a panelboard (or "load center," to use the phrase from this question) is unlikely to require maintenance while energized.

I would say it would depend on the loads served. If there are no loads that would be missed for the duration of the maintenance task, then I would say you can crowd a panel.

If it were the primary panel for a dwelling, I'd say it's highly unlikely that the panel will be de-energized for service.

I have a house panel on a sixplex that I have no room for, and install above the main disconnect. Technically, I am in violation of 110.26(A)(3), because the main disconnect sticks off the wall by 18", and I am only allowed 6". My argument was that there were no loads present that couldn't be shut off. It has:

* 1 120V 15A circuit for the fire-room GFI and keyless
* 1 240V 15A baseboard heater in that room,
* 1 240V 60A feeder for a detached garage, which supplies pole lights
* 1 120V 15A dedicated circuit for the horn strobe, which consists only of the 120V strobe switched by the flow. The LV fire alarm is on the other side of the flow, and is still operational when the flow closes contacts. Monitoring is not interrupted. In the unlikely event that a fire starts during the period of maintenance, the fire department will still be dispatched.

I would feel totally comfortable shutting down my house panel for maintenance. One factor I hadn't thought of: I should probably put a label on the panel to state it has no crucial loads, and can be momentarily disconnected for maintenance. Just because I know, doesn't mean the next guy will.

Besides, it's nice having the disconnect under it - it makes a good shelf for tools.

The AHJ was compassionate about the total lack of space I was given for the service, the phone and TV demarcs, and house panel. I gave up my prime panel location to ease the burden on the LV guys - there was literally no space for their undergrounds to emerge into a box on the wall, if I didn't move.

Commence with the rock throwing.

 

[pierre]

Re: Panel Location to Transformer

True story

Wednesday I did an inspection in a service room for a large building. Across the room from where I was inspecting was a typical transformer setup - panel, tranformer, disconnect. There was something different here though. Mounted to the top of the transformer and the wall behind the transformer is this fabricated metal (with louvers - to dissipate the heat) contraption. I asked the contractor what it was. He said the last inspector told him that the transformer top could be used as a shelf, and to install this item so that would not happen. I do have pictures if you would like to see this.

I explained to this particular inspector that his reasoning may be valid, but we do not inspect for "whatifs" and not to require this again.

 

[George Stolz]

Re: Panel Location to Transformer

To which, he mumbled under his breath as Pierre was walking away, "Short-timer."