Lighting Contactors
- Thread starter fblevins
- Start date
- Status
1793
Senior Member
- Location
- Louisville, Kentucky
- Occupation
- Inspector
Re: Lighting Contactors
I would think you could have either a normally "open" or "closed" contactor.
Norb
I would think you could have either a normally "open" or "closed" contactor.
Norb
- Location
- Massachusetts
Re: Lighting Contactors
IMO using NC lighting contactors is a good design practice and if you happen to be switching emergency lighting NC will be required.
By using NC contacts if (when) the coil gives out you will still have lighting.
Many lighting contactors come with reversible contacts so they can be converted from NO to NC.
IMO using NC lighting contactors is a good design practice and if you happen to be switching emergency lighting NC will be required.
By using NC contacts if (when) the coil gives out you will still have lighting.
Many lighting contactors come with reversible contacts so they can be converted from NO to NC.
- Location
- New Jersey
- Occupation
- Journeyman Electrician (retired)
Re: Lighting Contactors
We prefer mechanically held lighting contactors. The coil is only energized while it is changing from open to closed and vice versa. We've seen these things last forever without any problems. Our contactor of choice is the Asco 917. They come in various coil voltages, have many different control accessories and can control up to 12 circuits with one contactor. They're a little pricey but they seem to last forever.
We prefer mechanically held lighting contactors. The coil is only energized while it is changing from open to closed and vice versa. We've seen these things last forever without any problems. Our contactor of choice is the Asco 917. They come in various coil voltages, have many different control accessories and can control up to 12 circuits with one contactor. They're a little pricey but they seem to last forever.
- Location
- Massachusetts
Re: Lighting Contactors
I have replaced coils in Asco's, they are a pain to change glad they do not go often.
I do like the Asco but they only have a 50 / 50 chance of failing on.
I have replaced coils in Asco's, they are a pain to change glad they do not go often.
I do like the Asco but they only have a 50 / 50 chance of failing on.
john m. caloggero
Senior Member
Re: Lighting Contactors
The NEC does not require either NO or NC contacts for lighting control contactors. This is design consideration.
The NEC does not require either NO or NC contacts for lighting control contactors. This is design consideration.
- Location
- Massachusetts
Re: Lighting Contactors
John it may be a design decision but when switching emergency lighting Article 700 pushes us to using NC contactors.
- Location
- Windsor, CO NEC: 2023
- Occupation
- Hospital Master Electrician
Re: Lighting Contactors
How do you wire the control circuit for these? I've always wondered, but never had a chance to play with one.
- Location
- New Jersey
- Occupation
- Journeyman Electrician (retired)
Re: Lighting Contactors
Basically they have a coil that moves when it's energized. If you energize the common(L) and close(C) terminals the relay will latch in the 'on' position. There is a aux switch in series with both the open and close positions that stop power from reaching the coil once that position has been energized. This keeps the coil energized only for a fraction of a second.
Re: Lighting Contactors
geoege....not to leave you hanging...I guess its obvious, but then there is also the "unlatch" coil which you momnentarily energize to cause the contacts to change.
The mechanical contactors have the advantage of not consuming power while "on" , making no noise (Hummmmm) while on, and being easily controlled from multiple locations with momentary switches.
They are,however, as a rule, rather expensive as compared to their "electrically held" counterparts.
geoege....not to leave you hanging...I guess its obvious, but then there is also the "unlatch" coil which you momnentarily energize to cause the contacts to change.
The mechanical contactors have the advantage of not consuming power while "on" , making no noise (Hummmmm) while on, and being easily controlled from multiple locations with momentary switches.
They are,however, as a rule, rather expensive as compared to their "electrically held" counterparts.
- Location
- New Jersey
- Occupation
- Journeyman Electrician (retired)
Re: Lighting Contactors
Augie's got it right. You can use multiple momentary single pole, double throw switches to have control from many locations. Throw in a momentary time clock and you have an automatic lighting system with a manual override capability. Also, these contactors can be controlled from one location with a simple 3-way switch or single pole double throw timer.
Augie's got it right. You can use multiple momentary single pole, double throw switches to have control from many locations. Throw in a momentary time clock and you have an automatic lighting system with a manual override capability. Also, these contactors can be controlled from one location with a simple 3-way switch or single pole double throw timer.
paul
Senior Member
- Location
- Snohomish, WA
Re: Lighting Contactors
I just had to wire up several rooms where the emergency light fixture was switched with the rest of the fixtures in the room, but when power went out, the X fixtures had to come on. For this setup, I used 2 RIB relays in each room. One coil was activated by the switch leg power to switch the X power. The other was powered by the constant normal power to switch the X power through the NC contacts when a power loss was detected.
I just had to wire up several rooms where the emergency light fixture was switched with the rest of the fixtures in the room, but when power went out, the X fixtures had to come on. For this setup, I used 2 RIB relays in each room. One coil was activated by the switch leg power to switch the X power. The other was powered by the constant normal power to switch the X power through the NC contacts when a power loss was detected.
- Location
- New Jersey
- Occupation
- Journeyman Electrician (retired)
Re: Lighting Contactors
I have heard of installations such as this. However I would think that this would violate 700.3 unless that relays were approved for use on emergency systems.
- Location
- Windsor, CO NEC: 2023
- Occupation
- Hospital Master Electrician
Re: Lighting Contactors
Thanks, guys!
That's what I was wondering. So traveller "A" would be the "on" coil, and the "B" traveller would be the "off" coil. That's just cool.
Thanks, guys!
paul
Senior Member
- Location
- Snohomish, WA
Re: Lighting Contactors
That is interesting. I'll have to check the RIB's and see. I know for a fact that the inspector won't check it, but I'd like to find out for myself. We were wondering why the EE designed it this way in the first place. One lamp in a 2x2 3-lamp trouffer is on the X panel in each room. I would have just left them on 24/7. We're not talking a big savings in power by switching them.
paul
Senior Member
- Location
- Snohomish, WA
john m. caloggero
Senior Member
Re: Lighting Contactors
The original question did not specify that the contactor was for an emergency system. However, if it is for an emergency system, Section 700.6(C) requires an automatic transfer switch to "be electrically operated and mechanically held".
The original question did not specify that the contactor was for an emergency system. However, if it is for an emergency system, Section 700.6(C) requires an automatic transfer switch to "be electrically operated and mechanically held".
paul
Senior Member
- Location
- Snohomish, WA
Re: Lighting Contactors
One job I did he had me put the emergency lights, ie EZ-2 bugeyes, on the UPS system. I promptly called him up and asked if he wanted these lights to come on when the commercial power goes out, or only when the breaker feeding them trips. He then had me place them on the normal power source.
Which reminds me of another job I did for him. Same sort of scenario, but I had fixtures with the EM ballasts you mention. He had me put those on the UPS system. I thought about this and decided that I wouldn't call him up about it and just do as the print directed, but thought it was a waste of money for the EM ballast equipped light. During the walkthrough when we did the power outage test he wanted to know why the whole fixture was still lit up and not just the one lamp powered by the EM ballast. I showed him his print and that everything was working exactly how he drew it up. He wanted to change that until I told him I would send him a price for the change order. At that point he decided it was fine the way it was.
The system already in place is a generator backup with transfer switch to the required 700 system. The EM ballasts you mention are battery backup and the EE did not spec those. He has on other jobs I've done under him, but those jobs did not have to have article 700 emergency systems.
One job I did he had me put the emergency lights, ie EZ-2 bugeyes, on the UPS system. I promptly called him up and asked if he wanted these lights to come on when the commercial power goes out, or only when the breaker feeding them trips. He then had me place them on the normal power source.
Which reminds me of another job I did for him. Same sort of scenario, but I had fixtures with the EM ballasts you mention. He had me put those on the UPS system. I thought about this and decided that I wouldn't call him up about it and just do as the print directed, but thought it was a waste of money for the EM ballast equipped light. During the walkthrough when we did the power outage test he wanted to know why the whole fixture was still lit up and not just the one lamp powered by the EM ballast. I showed him his print and that everything was working exactly how he drew it up. He wanted to change that until I told him I would send him a price for the change order. At that point he decided it was fine the way it was.
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