We would like to retrofit 400W MH fixtures with industrial fluorescent fixtures having T5 lamps. The existing 400W MH fixtures are cord-and-plug connected to 15A, 277V twistlock receptacles. The branch circuit serving the twistlock receptacles is protected by a 30A breaker. Can we change out the metal halide fixtures to cord-and-plug connected fluorescent fixtures without changing out the 30A circuit breaker? NEC 410.30(C)(2) does not appear to apply since the fluorescent fixtures don't have a mogul base, but we seem to be meeting the intent of NEC 210.23(B).
Fluorescent fixtures on 30A circuit
- Thread starter dwayne7
- Start date
- Status
electricman2
Senior Member
- Location
- North Carolina
- Occupation
- Retired Electrical Contractor
Re: Fluorescent fixtures on 30A circuit
210.23(B)specifies only fixtures with heavy duty lampholders be used on a 30A branch circuit. IMO the fluorescent fixtures would not meet this requirement and could be only connected to a 20A circuit.
210.23(B)specifies only fixtures with heavy duty lampholders be used on a 30A branch circuit. IMO the fluorescent fixtures would not meet this requirement and could be only connected to a 20A circuit.
- Location
- Massachusetts
Re: Fluorescent fixtures on 30A circuit
240.5(B)(2)(4) requires 14 AWG fixture wires for a 30 amp circuit. The ballast leads are most likely 16 AWG.
You could put in line fuse holders in each fixture, many highbays have these built in.
I think I would just change the breakers.
240.5(B)(2)(4) requires 14 AWG fixture wires for a 30 amp circuit. The ballast leads are most likely 16 AWG.
You could put in line fuse holders in each fixture, many highbays have these built in.
I think I would just change the breakers.
renosteinke
Senior Member
- Location
- NE Arkansas
Re: Fluorescent fixtures on 30A circuit
I believe that you can have as large as a 50 amp lighting circuit- so 30 amp circuits powering more than 20 amps of small fixtures is OK.
Have you ever been inside one of those fancy billboard-type signs? The millions of bulbs are ganged up into large amperage circuits; often this means that each sign will require multiple panels.
A concern for you might be harmonics. If your site has three-phase power, the fluorescent electronic ballasts may overload the neutral. Something to watch out for, when you share neutrals.
I believe that you can have as large as a 50 amp lighting circuit- so 30 amp circuits powering more than 20 amps of small fixtures is OK.
Have you ever been inside one of those fancy billboard-type signs? The millions of bulbs are ganged up into large amperage circuits; often this means that each sign will require multiple panels.
A concern for you might be harmonics. If your site has three-phase power, the fluorescent electronic ballasts may overload the neutral. Something to watch out for, when you share neutrals.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Fluorescent fixtures on 30A circuit
renosteinke
Not so look at:
410.24 Conductor Insulation.
Luminaires (fixtures) shall be wired with conductors having insulation suitable for the environmental conditions, current , voltage, and temperature to which the conductors will be subjected.
Now look at:
(2) Fixture Wire. Fixture wire shall be permitted to be tapped to the branch circuit conductor of a branch circuit of Article 210 in accordance with the following:
(1) 20-ampere circuits ? 18 AWG, up to 15 m (50 ft) of run length
(2) 20-ampere circuits ? 16 AWG, up to 30 m (100 ft) of run length
(3) 20-ampere circuits ? 14 AWG and larger
(4) 30-ampere circuits ? 14 AWG and larger
(5) 40-ampere circuits ? 12 AWG and larger
(6) 50-ampere circuits ? 12 AWG and larger
I haven't yet seen a #12 on a ballast yet?
renosteinke
Not so look at:
410.24 Conductor Insulation.
Luminaires (fixtures) shall be wired with conductors having insulation suitable for the environmental conditions, current , voltage, and temperature to which the conductors will be subjected.
Now look at:
(2) Fixture Wire. Fixture wire shall be permitted to be tapped to the branch circuit conductor of a branch circuit of Article 210 in accordance with the following:
(1) 20-ampere circuits ? 18 AWG, up to 15 m (50 ft) of run length
(2) 20-ampere circuits ? 16 AWG, up to 30 m (100 ft) of run length
(3) 20-ampere circuits ? 14 AWG and larger
(4) 30-ampere circuits ? 14 AWG and larger
(5) 40-ampere circuits ? 12 AWG and larger
(6) 50-ampere circuits ? 12 AWG and larger
I haven't yet seen a #12 on a ballast yet?
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