Mounting fluorescent fixtures

[Karl Fields]

My barn has 20' ceilings. In the process of installing about 30 4 tube, 4' t8's at the 12' level.

The original concept was to simply use the old chain hanging technique, but it looks a little messy. Now to get power to them I need to use run MC cable. What the heck do I do, install the cable at the 20' level and run it down to the fixture? Of course it would need to go back to the ceiling to continue to the next fixture. Seems like a waste of cable, 16'+ for each fixture.

Not that we have an inspector, but how would I secure the cable within the 12" limit?

Conduit from fixture to fixture at the 12' level would work, I guess.

How would you guys mount the fixtures to the 20' ceiling?

 

[ForceFed70]

Put a junction box at the ceiling. You don't need to run 2 cables to the fixture.

Hanging the fixtures is the only option that I know of. You can run the cable straight down or have it follow one of the chains.

 

[G'ord]

Depending on your finances you may want to consider installing t5 high bay fixtures which provide much better light than HID high bays. they can be installed 6" from the ceiling. you will need less high bays than you t8 fixtures.

Another option is the use of uni-strut to and hang the fixtures from them.

how big is the space?

oh i forgot you might be able to run one cable to the first fixture then directly from fixture to fixture from that one esp. if you're using MC

 

[Karl Fields]

Well of course I should use a J-box on the ceiling. Must of had an elder moment!

T5s aren't in the budget - barn is way over as it is.
Uni-strut is a good idea. Might look into that as smaller purchases can slide under the radar
.

 

[Norcal]

If the fixtures are chain mounted they cannot be fed w/ MC as MC has solid conductors & they (the conductors) need to be stranded. 410.56(E).

Hanging strip fixtures is easy, jack chain & Vee hangers, but flexible metal conduit w/ stranded conductors will have to be used to feed power, just attach the flex to the jack chain w/ zip ties.

 

[Karl Fields]

If the fixtures are chain mounted they cannot be fed w/ MC as MC has solid conductors & they (the conductors) need to be stranded. 410.56(E).

Tryng to understand this. Is it because the chain allows movement and solid conductor may be more prone to failure with movement?

Hanging strip fixtures is easy, jack chain & Vee hangers, but flexible metal conduit w/ stranded conductors will have to be used to feed power, just attach the flex to the jack chain w/ zip ties.

What is a Vee hanger?

 

[Norcal]

Tryng to understand this. Is it because the chain allows movement and solid conductor may be more prone to failure with movement?


What is a Vee hanger?

Wrong description.

http://www.drillspot.com/products/434256/Lithonia_HC36_M12_Chain_Hanger

The hangers should be avail in bulk at a supply house, & jack chain is avail in bulk also.

 

[tfi racing]

If the fixtures are chain mounted they cannot be fed w/ MC as MC has solid conductors & they (the conductors) need to be stranded. 410.56(E).

Hanging strip fixtures is easy, jack chain & Vee hangers, but flexible metal conduit w/ stranded conductors will have to be used to feed power, just attach the flex to the jack chain w/ zip ties.

Interesting,no requirement up here for stranded conductors for suspended fixtures,AC90 still acceptable,as well as various flexible cables.

 

[Modifieddriver]

Wrong description.

http://www.drillspot.com/products/434256/Lithonia_HC36_M12_Chain_Hanger

The hangers should be avail in bulk at a supply house, & jack chain is avail in bulk also.

$8.78 chain hanger for each light. OUCH.

I wonder what the bulk qt'y price would be?

 

[Aceman]

If the fixtures are chain mounted they cannot be fed w/ MC as MC has solid conductors & they (the conductors) need to be stranded. 410.56(E).

Hanging strip fixtures is easy, jack chain & Vee hangers, but flexible metal conduit w/ stranded conductors will have to be used to feed power, just attach the flex to the jack chain w/ zip ties.

They make stranded MC, it's what I use for chain hung fixtures.

 

[Karl Fields]

They make stranded MC, it's what I use for chain hung fixtures.

Why is stranded needed for hanging fixtures?

 

[Norcal]

Why is stranded needed for hanging fixtures?

Flexibility.

 

[wingfootedgodhead]

Depending on your finances you may want to consider installing t5 high bay fixtures which provide much better light than HID high bays. they can be installed 6" from the ceiling. you will need less high bays than you t8 fixtures.
C

I was under the impression that T5HO could be flush mounted ?

 

[madosta]

I was under the impression that T5HO could be flush mounted ?

It all depends on the particular fixture, not the bulb type. There are T8 and T5 fixtures that are capable of being flush mounted. The ones with chains and cords typically are not allowed to be flush mounted. If you look at a lighting/electrical supply house they usually have a display section with some industrial lights.

IMHO, if I were you... even have spent so much already, I would look into T5 HO high bays... A little pricy, but WOW are they bright. You might be able to get away with a few for now, and then add more as you can afford.

 

[2Big2Ride]

If the fixtures are chain mounted they cannot be fed w/ MC as MC has solid conductors & they (the conductors) need to be stranded. 410.56(E).

Hanging strip fixtures is easy, jack chain & Vee hangers, but flexible metal conduit w/ stranded conductors will have to be used to feed power, just attach the flex to the jack chain w/ zip ties.

Is this requirement only if fixtures are hanging on chains?

I have MC 12/2 solid following the threaded rod down from the ceiling to boxes mounted on strut. The strut assembly is hanging from the ceiling using six beam clamps, each with threaded rod from the clamp to strut.

 

[hunt4cleanair]

This has been a great discussion. I am thinking of drywalling my ceiling and trying to figure out the lighting. currently I have fixtures hanging from chain but my electrician that it needs to be redone. I only have an 8' ceiling and its pretty Mickey Mouse...no offense Mickey!