Em ballast/battery back-up

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Alwayslearningelec

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Is there a difference between the two and if so what is it? Thanks.

Also, have you ever seen fixtures on a EM circuit(generator) with em ballast/ battery backup)

Thanks.
 
An emergency ballast is a battery. Usually does 1 of the tubes in a fixture.

Batteries are still used on generator lighting circuits because of the time it takes to start.
 
Also, have you ever seen fixtures on a EM circuit(generator) with em ballast/ battery backup)

Thanks.[/QUOTE]

Yes, we have that very setup at our shop, but not by design.... the genny was added a few years later.;)
 
defears said:
An emergency ballast is a battery. Usually does 1 of the tubes in a fixture.

Batteries are still used on generator lighting circuits because of the time it takes to start.
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So battery backup means it has an EM ballast? Also, when the designation on a drawing says EM/NL whcih means emergency nightlight what exactly is that. Is that different than just an EM designation? THanks.
 
horsegoer said:
So battery backup means it has an EM ballast? Also, when the designation on a drawing says EM/NL whcih means emergency nightlight what exactly is that. Is that different than just an EM designation? THanks.
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Yes, I would normally call battery backup the same as an EM ballast. Although, you can also have a central battery system that runs multiple standard light fixtures.

A nightlight would be unswitched: it stays on 24/7.

You can also have fixtures with an EM ballast that are switched. If power is lost while they are switched off, they turn on. The do this by monitoring a separate unswitched hot wire.

P.S. Emergency ballasts can also be integral to the fixture, or they can be remote mounted.
 
There are two types.. Generator rated and standard. The generator rated one puts out nearly full output for a few minutes. Standard is usually rated for 90 minutes of battery life
 
Most of these lights I've worked with are a pain. I always reccomend a separate EM wallpack light, much simpler & more reliable. I've seen some 2x4 troffers with EM ballasts & 2 std ballasts that seem to lose a ballast once a year or more.
 
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