high bays blowing capacitors

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bowman

Member
I haven't had this problem before..... the situation is a wharehouse relamp. Total amount of fixtures is approx. 166. All 400 watt mh highbays. The first phase consisted of about 50 where upon energizeing them I had about 5-6 capacitors go. Not all at the same time and since it was ab switching I didnt energize all 50 at once either. Then next day had couple more go and 3rd day the same at diferent times and some after they have been burning for a few hours(total of 12 ). fixtures are wired 480v fed from 20 amp breakers through lighting contactors. lights are dropped level height by 3/4 rigid niples cut from close to 24''....
any help or advice is apreciated
also had the lighting rep and tech support out which i was very appreciative of their help and fast response to the situation...
however just wanted to throw it out and see if i can learn something..
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Re: high bays blowing capacitors

Well what did the rep and tech support guys say? Sounds to me like these caps needed to be replaced, you don't say how old these fixtures are. Another factor may be not replacing the lamps in a timely manner. If left to cycle they will take a toll on the other components. I should also mention that heat is a big factor also.

-Hal

[ November 04, 2004, 01:23 PM: Message edited by: hbiss ]
 

hurk27

Senior Member
Re: high bays blowing capacitors

The only times I had this happen is:
1. 120 volt lighting on a shared nutral. lost the neutral
2. 277 volt same as above
3. Installed the wrong bulbs 250 watt instead of 400 watt :eek:

I didn't think we were allowed to install 480 volt fixtures on the inside of a building?
I thought it is a requirment to not have over 300 volts between the ungrounded conductors?
 

bowman

Member
Re: high bays blowing capacitors

thanks for the replys......
age of fixtures is right out of box date on box of when produced I will have to verify but I think it was a june date???

at a glance 210-6 c circuit doesnt exceed 277 to ground however is 480 phase to phase

could you let me know what code you are refering to
thanks again
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Re: high bays blowing capacitors

Well, then it sounds like the manufacturer's problem. Can't see what you did wrong.

Wayne, I never heard of that one. Obviously too is that they make these things and they should be listed. :confused:

-Hal
 

iwire

Moderator
Staff member
Location
Massachusetts
Re: high bays blowing capacitors

Maybe it was 410.75 under discussion?

This section does not limit the voltage of the branch circuit.


410.75 Open-Circuit Voltage Exceeding 300 Volts.
Equipment having an open-circuit voltage exceeding 300 volts shall not be installed in dwelling occupancies unless such equipment is designed so that there will be no exposed live parts when lamps are being inserted, are in place, or are being removed.
There is 210.6(A) which limits voltage between conductors in some occupancy's.

210.6 Branch-Circuit Voltage Limitations.
The nominal voltage of branch circuits shall not exceed the values permitted by 210.6(A) through (E).

(A) Occupancy Limitation. In dwelling units and guest rooms of hotels, motels, and similar occupancies, the voltage shall not exceed 120 volts, nominal, between conductors that supply the terminals of the following:

(1)Luminaires (lighting fixtures)

(2)Cord-and-plug-connected loads 1440 volt-amperes, nominal, or less or less than 1/4 hp
IMO 210.6(D)(2) allows the use of 480 volt HID fixtures in occupancy's not mentioned in 210.6(A)

210.6(D) 600 Volts Between Conductors. Circuits exceeding 277 volts, nominal, to ground and not exceeding 600 volts, nominal, between conductors shall be permitted to supply the following:

(1)The auxiliary equipment of electric-discharge lamps mounted in permanently installed luminaires (fixtures) where the luminaires (fixtures) are mounted in accordance with one of the following:

a.Not less than a height of 6.7 m (22 ft) on poles or similar structures for the illumination of outdoor areas such as highways, roads, bridges, athletic fields, or parking lots

b.Not less than a height of 5.5 m (18 ft) on other structures such as tunnels

(2)Cord-and-plug-connected or permanently connected utilization equipment

FPN:See 410.78 for auxiliary equipment limitations.

Exception No. 1 to (B), (C), and (D): For lampholders of infrared industrial heating appliances as provided in 422.14.

Exception No. 2 to (B), (C), and (D): For railway properties as described in 110.19.
 
Re: high bays blowing capacitors

Bowman,

Have dealt with such cases, and in each it was a different fault. Need more info. Any chance you could write directly? If appropriate, we can then post the results of any findings here for others to benefit by.

Marc Dekenah
Fault investigation and analysis consultant

Edited to remove the e-mail address

[ November 06, 2004, 06:44 PM: Message edited by: charlie ]
 

hurk27

Senior Member
Re: high bays blowing capacitors

Now I see what they were talking about.
If a plant had a 480 volt grounded delta it could not be used to supply lighting fixtures unless they met the requirments in 210.6(D)(1)a.

210.6(C) 277 Volts to Ground. Circuits exceeding 120 volts, nominal, between conductors and not exceeding 277 volts, nominal, to ground shall be permitted to supply the following:
(1) Listed electric-discharge luminaires (lighting fixtures)
(2) Listed incandescent luminaires (lighting fixtures), where supplied at 120 volts or less from the output of a stepdown autotransformer that is an integral component of the luminaire (fixture) and the outer shell terminal is electrically connected to a grounded conductor of the branch circuit
(3) Luminaires (lighting fixtures) equipped with mogul-base screw shell lampholders
(4) Lampholders, other than the screw shell type, applied within their voltage ratings
(5) Auxiliary equipment of electric-discharge lamps
(6) Cord-and-plug-connected or permanently connected utilization equipment
210.6(D)(1) a. Not less than a height of 6.7 m (22 ft) on poles or similar structures for the illumination of outdoor areas such as highways, roads, bridges, athletic fields, or parking lots
Bob, this is what they were talking about as they were talking about the wording being changed in the "2005"

Here is what the Analysis of Changes 2005 NEC say's:
New wording was added to clarify that luminaires (lighting fixtures) are not permitted by this section to be connected to a circuit with voltage that exceeds 277 volts to ground. Since luminaires fall within the description of electrical equipment, the previous wording apparently has been interpreted to permit ballasts of HID fixtures installed in industrial buildings to be connected to a 480 volt delta-connected system. The added wording will make it clear that luminaires are not permitted to be connected to a circuit exceeding 277 volts unless provisions in 210.6(D)(1) are met.

change at a Glance
The wording "other than luminaires (fixtures)" was added to the first sentence of 210.6(D)(2).
This is verbatum out of the book.

[ November 06, 2004, 07:20 PM: Message edited by: hurk27 ]
 

hurk27

Senior Member
Re: high bays blowing capacitors

Bowman I was wrong about the 480 volts between phases it's more than 300 volts to ground.Bob got me diggen and I found it after going through some of my book's.

Edited to delet my brain fart :eek:

[ November 06, 2004, 11:59 PM: Message edited by: hurk27 ]
 
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