2 lamps on a 4 lamp t8 ballast

[-=PEAKABOO=-]

Does anyone know if it will damage a 3-4 lamp electronic t-8 ballast if it is only used with 2 lamps? It is a 48' 4 lamp fixture and i would like to inboard outboard the fixture using a relay on the leads feeding the sockets.

Thanks for any help

 

[iwire]

Most electronic ballast just say to cap unused leads.

 

[LarryFine]

As Bob said, but I'm just cheap enough to swap out that ballast for a 2-tube model, and save the 3-4-tube one for a 3-4-tube application.

 

[eljefetaco]

I haven't done a amp reading, but does anyone know if you waste energy using a four lamp ballast as a two lamp. I was at the Hertz Corporate office and noticed they are removing one lamp from hundreds of fixtures. I would think there is some energy savings, but could also waste money and damage the ballasts. Any thoughts

 

[cschmid]

man that is complicated method of switching light. no sir it does not waste energy if only two are connected it only uses that amount of energy and when you are talking .045 amps on 4 bulbs it is minute. That is an approximation on the amp draw as I did not look up a ballast to be exact.

 

[-=PEAKABOO=-]

As Bob said, but I'm just cheap enough to swap out that ballast for a 2-tube model, and save the 3-4-tube one for a 3-4-tube application.

I am wanting to inboard outboard switch the fixtures by using a relay to kill power to 2 lamps(4 lamp fxture with 1 ballast). The fixtures are brand new, installed, have 2 switch legs and 1 4 lamp ballast.

I know that at least one switch would have to be on to power ballast. It just like it would be a little easier and cheaper (I have the relay) then adding another ballast

 

[-=PEAKABOO=-]

man that is complicated method of switching light. no sir it does not waste energy if only two are connected it only uses that amount of energy and when you are talking .045 amps on 4 bulbs it is minute. That is an approximation on the amp draw as I did not look up a ballast to be exact.

Yes I know. I will probably be adding another ballast.

 

[LarryFine]

I am wanting to inboard outboard switch the fixtures by using a relay to kill power to 2 lamps(4 lamp fxture with 1 ballast). The fixtures are brand new, installed, have 2 switch legs and 1 4 lamp ballast.

I know that at least one switch would have to be on to power ballast. It just like it would be a little easier and cheaper (I have the relay) then adding another ballast

You'd need a multi-pole relay in each fixture, using the second line conductor to energize them. Plus, that relay would have to be capable of handling approx. 600v.

I'd still go with two 2-lamp ballasts in each fixture. Didn't they know they would want separate-pair operation before the fixtures were ordered?

 

[-=PEAKABOO=-]

I'd still go with two 2-lamp ballasts in each fixture. Didn't they know they would want separate-pair operation before the fixtures were ordered?

I mentioned it to them, there never said they wanted it that way. They claimed I bid it that way but I did not. I have 32 fixtures like this. The contractor that I am doing the work for is throwing a fit about having to pay claiming I told him I would do it this way. Just trying to way options here. It was kind of my mistake by not thinking to order fixtures with dual ballast. I am at least going to try to get him to cover the difference in ballast price which is roughly how much extra the proper fixtures would cost.

 

[K2X]

Have you considered running 1 4 lamp ballast for two fixtures and the other 4lamp ballast for two fixtures. That would give you inboard outboard. I don't know your arrangment but you said you had two switch legs. If the fixtures are end to end it would be really simple but if your in a grid you could throw an 18 gauge whip. I've don a thousand master/slaves using 4 lamp ballast with whips so it would be kinda the same thing. Maybe??

 

[K2X]

Have you considered running 1 4 lamp ballast for two fixtures and the other 4lamp ballast for two fixtures. That would give you inboard outboard. I don't know your arrangment but you said you had two switch legs. If the fixtures are end to end it would be really simple but if your in a grid you could throw an 18 gauge whip. I've don a thousand master/slaves using 4 lamp ballast with whips so it would be kinda the same thing. Maybe??

I can't find the edit button. Anyway , to restate. One ballast would run the inboard on two fixtures and the other ballast would run the outboard on two fixtures.

Usually the label states how many leads are approved for capping off. I know the ballast would work with two capped off but i havn't seen and approved for that..

 

[LarryFine]

Have you considered running 1 4 lamp ballast for two fixtures and the other 4lamp ballast for two fixtures.

Interesting. You'd need a 'whip' with three conductors going each way (in addition to the line conductors) between each pair of fixtures, if I'm correct.

 

[Cow]

I'd swap out the 4 lamp ballasts for two 2 lamp instead, before I'd use a relay on the tombstone leads. Just my opinion...

 

[K2X]

Interesting. You'd need a 'whip' with three conductors going each way (in addition to the line conductors) between each pair of fixtures, if I'm correct.

Sounds like he had two switch legs in each fixture but , you could put both ballast in one fixture and whip to the slave/empty fixture and still do the inboard outboard thing. If I'm reading the OP correctly this would eliminate buying more ballast and capping off two leads. I've capped one lead plenty of times but have only capped two leads on my own house.

 

[cschmid]

I can't find the edit button. Anyway , to restate. One ballast would run the inboard on two fixtures and the other ballast would run the outboard on two fixtures.

Usually the label states how many leads are approved for capping off. I know the ballast would work with two capped off but i havn't seen and approved for that..

that is the best idea here so far and it will work with just wiring but labor might eat up cash as well.

maybe see if you can return them and but 2 ballast fixtures..unless installed already.

 

[HotConductor]

IMO the inboard/outboard option would void the UL listing on the fixtures.

 

[-=PEAKABOO=-]

I opted to cap off 2 leads of the 4 lamp ballast and install another 2 lamp ballast.
Does anyone see a problem with capping off 2 leads?

 

[LarryFine]

Does anyone see a problem with capping off 2 leads?

Only waste.

 

[-=PEAKABOO=-]

Next question, has anyone seen any 4 lamp wrap around fixtures lately with 2 ballast that can be used for inboard outboard switching?

 

[cschmid]

Next question, has anyone seen any 4 lamp wrap around fixtures lately with 2 ballast that can be used for inboard outboard switching?

yes lithonia make them and I am working with a bunch right now..now inboard outboard does not void the warranty..the engineer on the job now has designed lighting schemes that the inner bulbs on the fixture are together and the outer bulbs are together. The ballast are programmed ballasts and when the bulbs in one fixture go out they affect the bulbs in the other fixture. Special ballast and every thing. mounts on the j-box and hooks to the lights with whips..