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vaughn
@192.82.150.x

vaughn

Anon

[Electrical] Fuses keep breaking in 400amp panel

I'm hoping some of you have some ideas. I work in a theatre and we have 4 @ 400amp 3phase panels backstage. we use only one primarily and the indicator lights keep blowing their fuses. We used to have 1amp fuses but have switched over to 3amp fuses and they are still blowing. Our electrician doesn't know why so i thought i would look online. I've attached a photo of the panel in which you can see the top to lights are blown. Any advice would be helpful!
Speedy Petey
join:2008-01-19

Speedy Petey

Member

[Electrical] Re: Fuses keep breaking in 400amp panel

WHY are you doing the electrician's job for him??? If he cannot figure out why, find someone who can.

This is not even remotely withing the scope of " Home Improvement".
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vaughn
@192.82.150.x

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Anon

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[Electrical] Re: Fuses keep breaking in 400amp panel

hi and thanks i'm aware that it's not within the scope of home improvement but I've contacted a few different electricians and none of them can figure it out. I thought i would put it out to any electrician for ideas. that's all.

PoloDude
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join:2006-03-29
Aiken, SC

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No picture. What are the indicator lights for? Do you have a schematic?

vaughn
@192.82.150.x

vaughn

Anon

Click for full size
here's a photo. the indicator lights are so we know that everything is connected properly and there are no issues...to my understanding anyway. sometimes it's just a bulb that blows but more often than not it's a fuse that blows.

tp0d
yabbazooie
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join:2001-02-13
Bulger, PA

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Do the status lights come on only when theres current flow on each ckt? Or just when the plug is inserted (properly)?

You may have terminal problems at the connector. If one terminal is loose/contacting another or gnd, it may over load the status light ckt and blow the fuse.

Some pics of the terminal ends and a pic of the wiring/control ckt for the status lights would help.

edit.. lookin at the pic again, those are prob 2 pole leads, and there would be some sort of continuity ckt driving those status bulbs. Problem would most likely be the control board itself for the status lites. Need a pic inside box

-j
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IowaCowboy
Lost in the Supermarket
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join:2010-10-16
Springfield, MA

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[Electrical] Re: Fuses keep breaking in 400amp panel

Even worse is an electrician replacing a fuse with a higher rating. My high school shop teacher would call that a spark and flame show waiting to happen.

Pretty soon you'll have a fire. I hope this isn't a historic theater that will be a tragic loss when it burns down. I'm saying when not if it burns down.

Get a competent electrician in there, not some cut rate hack job. Maybe the equipment needs replacing. Many of these theaters are historic treasures.

BurntAgain
@rr.com

1 recommendation

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Anon

to vaughn
Are you talking to real Licensed Electricians or guys that "do electrical work" ?? A real licensed Electrician will be able to circuit trace and troubleshoot and be able to tell you EXACTLY what your issue is... Hint at least one of them isn't a licensed Electrician? Sticking a larger fuse in a blown ones place, unless the circuit WAS designed for a larger fuse.
Hellrazor
Bah Humbug
join:2002-02-02
Abyss, PA

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I am not familiar with that lighting control setup. I have 2 Lehigh setups at work. I go directly to Lehigh to resolve issues when I am done troubleshooting on my own. I don't get electricians involved for a lighting control issues unless the Manu needs one to make repairs.

Make sure the fuses are being replaced with the the proper type. Not that someone just threw something in that was just handy. Kind of like throwing a 3A in for a 1A. Are the fuses on a control card?

sparks26
@rr.com

1 recommendation

sparks26

Anon

It's not a "lighting control setup", it's a company switch. Touring companies come into a venue and tie their equipment into the 3 phase cam-loks.

Part of the problem could be that "electrician" in the theatre world does not equal "electrician" or "electrical contractor" in the construction world. Theatre electricians are the ones who hang, focus, and control lights for shows.

I recommend the OP find the contractor who installed the system and go from there.

leibold
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Re: [Electrical] Fuses keep breaking in 400amp panel

If someone replaced 1A fuses with 3A fuses then there is a good chance that at some point the indicator lamps where replaced with wrong ones too (either by the same person or someone with similar lack of qualification for the job). If the replacement indicator lamps take a much higher current then the original lamps then that would explain the fuses blowing.

vaughn
@192.82.150.x

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Anon

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Thanks for all the advice. I work at the theatre and we are not allowed to open it up to see the fuses or the inside. We have an electrical contractor that comes in to do all of our building electrical work as we are not qualified to do it (you are very right sparks26) i'm in the process of trying to find the original contractor as well to see what they have to say. It's great to get your opinions thank you.

whizkid3
MVM
join:2002-02-21
Queens, NY

2 recommendations

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I suggest you call the manufacturer of the Cam-Lok boxes. Second suggestion is to replace the indicator lamps with lamps matching the originals. They were likely replaced with the wrong lamps, by a stage electrician who is used to trying to make things work in a hurry, with whatever they have available. Get the right bulbs, get the right fuses; and then if it still blows the fuses, they need to be diagnosed. I would recommend by a manufacturer rep.

As to what the lamps do; I have no real idea other than power indication (which does not explain the ground indicator). THe box is nothing more than a circuit breaker box, with an incoming feeder; a circuit breaker, feeding five Camlok connectors.
alphageek911
join:2007-08-10
Fresno, CA

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It seems unlikely only the pilot lamps are connected to the fused circuit: the lamps would have to be dissipating well over 120 watts to blow even a one amp fuse, and over 360 watts to blow a 3 amp fuse.

I wouldn't expect any pilot lamps like what's in that panel to draw over a few watts, at most. If there are bad contacts/main fuses/breakers, etc., the panel might be trying to supply the main lighting load through the pilot light circuit, which would blow those fuses.

A qualified electrician needs to look at that panel and see if there is an excessive drop inside the panel.

Satman2222
@xx.net

Satman2222

Anon

Has the neutral line broken on the control circuit and the bulbs are blowing because they are effectively across 2 phases?

mackey
Premium Member
join:2007-08-20

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said by whizkid3:

As to what the lamps do; I have no real idea other than power indication (which does not explain the ground indicator).

My guess is there is a switch in the camlok connector and the light lights when the camlock is fully inserted and locked.
mackey

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Managed to find the manufacture, unfortunately this is the closest thing to a diagram I've found and while it lists part #'s it doesn't show how the lights are wired. Looks like it's not complex though so any competent electrician should be able to figure it out.

/M

John Galt6
Forward, March
Premium Member
join:2004-09-30
Happy Camp

John Galt6

Premium Member

"Fused indicator lights shall be provided for each phase and ground continuity."

»www.ssrconline.com/pdf/2 ··· 20r1.pdf

leibold
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join:2002-07-09
Sunnyvale, CA

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Not only does it not show how the lamps are wired, the part number given for the pilot lamps is a universal lamp holder and not the part number for the lamp itself (which may be any T2.5 or T3.25 bulb).

aurgathor
join:2002-12-01
Lynnwood, WA

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Can you figure out at what point do you blow the fuses?

What type of switches do you have downstream? Make before break, break before make, or something else? What lines are being switched? Do you have some inductive loads in there? Can your electrician hook up a recording voltmeter such as the Fluke 289?

KA0OUV
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Jefferson City, MO

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Re: [Electrical] Re: Fuses keep breaking in 400amp panel

Bulbs and fuses not at correct voltage rating? Make sure you have the right bulbs and fuses at 250V rating.

The folks at the company can probably get you the rest of the info you need.

whizkid3
MVM
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Queens, NY

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Re: [Electrical] Fuses keep breaking in 400amp panel

said by mackey:

My guess is there is a switch in the camlok connector

There is not. Its just a single-wire connector for large wires. See attached for typical Camlok stud. The downstream wire has a male Camlok connector that 'snaps' into the female part.
harald
join:2010-10-22
Columbus, OH

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Is the theater IATSE?

whizkid3
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Queens, NY

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Part numbers from the wiring diagram that mackey See Profile found:

The bulbs (mini-bayonet) come in all different voltages. Most likely the problem is that the electrician is using the wrong voltage bulb. Simple. Call the manufacturer and find out what voltage bulbs to use. Then (or before that) replace the fuses with the right ones. Problem solved. No need for a Dranetz recording meter.

StillLearn
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join:2002-03-21
Streamwood, IL

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I would consider pulling the bulbs and see if fuses still blow. If not, inspect the bulbs to see if one looks different. If so, sounds like a short in the panel.

whizkid3
MVM
join:2002-02-21
Queens, NY

whizkid3

MVM

It sounds like the wrong voltage bulbs.
TheMG
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Canada
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I suspect this is more than just incorrect bulbs. Especially since it's blowing 3A fuses.

Might want to see if there's something in the panel beyond just simple switches, fuses, and indicator lamps. Perhaps there's some circuitry in there that does some type of sensing to determine if something is connected.

If so, then it is possible there's a problem with the circuitry driving the lamps and this could be why it's blowing fuses.

There is also a remote possibility that there is nothing wrong, and that the bulbs are occasionally causing the fuses to pop when they burn out. Sounds far-fetched but I've seen it happen before, when the filament inside a lamp breaks, falls, and creates a short inside the bulb itself, enough to blow the fuse. It is relatively rare but can happen.

whizkid3
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Queens, NY

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What happened with your phone call to the manufacturer?