Have a ? for everybody yesterday wired a garage with 8 8 foot flourescent lights an recepts. Its a 120/240 service. I split the lights on 2 circuits 4 lights each on a 20A . After hooking up power took some amp readings an noticed I had put the 2 lighting circuits on the same phase an was pulling 14 amps on phase B an 14 amps on the neutral. So I moved one to the other phase an was getting 7 amps on each phase but was getting 7 amps on the neutral. Is this normal? Hooked a drill up on a recept an ran it an the current on the neutral dropped some. This kinda threw me can anyone here shine some light on this for me? Should there be current like this on the neutral from the lighting?
Question about neutral current?
- Thread starter bbe
- Start date
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hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Question about neutral current?
Not if you have equal current on the phase conductors, Your saying you have 7 amps on each phase and 7 amps on the neutral? are you sure you didn't get a neutral crossed at a juntion box some where? If the drill droped the neutral current then it sounds like one of the lighting neutrals are crossed with the receptacle neutral.
Where are you taking these readings?
Not if you have equal current on the phase conductors, Your saying you have 7 amps on each phase and 7 amps on the neutral? are you sure you didn't get a neutral crossed at a juntion box some where? If the drill droped the neutral current then it sounds like one of the lighting neutrals are crossed with the receptacle neutral.
Where are you taking these readings?
- Location
- Illinois
- Occupation
- retired electrician
Re: Question about neutral current?
Are you sure that it is 120/240 and not two hots and a grounded conductor from a wye system?
Don
Are you sure that it is 120/240 and not two hots and a grounded conductor from a wye system?
Don
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: Question about neutral current?
I am thinking along the same lines as Don. When the two hots are 120 degress of phase apart from each other, then 7 (on one hot) plus 7 (on the other hot) is going to be 7 (on the neutral).
[ November 25, 2005, 11:15 AM: Message edited by: charlie b ]
I am thinking along the same lines as Don. When the two hots are 120 degress of phase apart from each other, then 7 (on one hot) plus 7 (on the other hot) is going to be 7 (on the neutral).
[ November 25, 2005, 11:15 AM: Message edited by: charlie b ]
john m. caloggero
Senior Member
Re: Question about neutral current?
Is this a residential garage or commercial garage. If it is commercial it may be supplied by a three phase wye system. It sounds like you are connected to two phases and the neutral of a three phase system
Is this a residential garage or commercial garage. If it is commercial it may be supplied by a three phase wye system. It sounds like you are connected to two phases and the neutral of a three phase system
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: Question about neutral current?
What brand is the meter?
What brand is the meter?
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Re: Question about neutral current?
Who's on first?
Who's on first?
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: Question about neutral current?
I don't know.
I don't know.
kbsparky
Senior Member
- Location
- Delmarva, USA
Re: Question about neutral current?
Are you by chance using electronic ballasts? Those can cause harmonics in the neutral resulting in what would appear to be unbalanced readings ..
Are you by chance using electronic ballasts? Those can cause harmonics in the neutral resulting in what would appear to be unbalanced readings ..
stud696981
Senior Member
Re: Question about neutral current?
This sounds like a single phase service, if so harmonics won't be an issue.
This sounds like a single phase service, if so harmonics won't be an issue.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: Question about neutral current?
"Harmonics" is just another way of saying the voltage and/or the current is not a pure sine wave. That can happen in single phase as well as in three phase.
"Harmonics" is just another way of saying the voltage and/or the current is not a pure sine wave. That can happen in single phase as well as in three phase.
- Location
- Illinois
- Occupation
- retired electrician
Re: Question about neutral current?
Don
True, but the harmonic currents do not add in the neutral on single phase system like they do on three phase wye systems.
Don
- Status