Dimming Lights?

[nadprosper]

Hi, I'm new here and just want to jump right in. Ok....so here is a problem that we never found a satisfactory explanation for. We wired an addition on a house that had two bedrooms, a bathroom and a large hallway with several can lights. We ran a 14/3 split to pick up the bedrooms and the hallway and we ran a 12/3 split for the bath and some outside receps. No problem with the 20 amp circuits, but we got a call from the client because she was concerned that her lights in the bedrooms were dimming when she ran her hairdryer or her vacuum ( both large loads ) I should note that each bedroom had it's own 15 A circuit...with the hallway sharing one bedroom....and each room had 2 can lights ( 50 w ) and 2 halogen sconces ( 150 w )...and the hallway had 4 cans ( 50 w ) and 2 halogens ( 150 w )...for a total lighting load of 900 w on one of the circuits. Now, I know that a large load can cause the lights to dim....but my experience has shown that this usually happens in older homes. We went to check it out and found the lights did dim very noticeably, in both rooms. We tried to explain that this was a common thing...but she said it hadn't happened elsewhere in the house...and sure enough....she was right. We thought it may be a voltage drop ( unlikely...homeruns were only 100ft ) but we changed the 14/3 to a 10/3 just to be sure.....no change. We suggested it may be due to the halogens...but that was kind of a guess........ok guys ( and gals ) whattaya think......thanx

 

[BackInTheHabit]

What size service does the house have?

 

[Lxnxjxhx]

See page 6 of the Ideal 61-164 manual.

 

[nadprosper]

100 amp...what is the ideal manual?

 

[Dennis Alwon]

I am assuming you did not use arc faults in this circuit since you ran a 14/3. My guess is you may have a loose connection somewhere on the grounded conductor simply because that is the common link between the circuits. If the panel is a sub I would check the grounded conductor on the feeder on both ends.

 

[nadprosper]

I did use an arc fault...they have 2 pole breakers for those...would that make a difference....I seem to recall thinking that and may have even bypassed them...not sure. Also, we did check the connections at the panel and in the drop off point....but there could vave been one we missed.......

 

[Dennis Alwon]

If you used a dp arc fault that should not be the problem unless it is defective and has a bad neutral connection on it. Stick a reg. breaker in and see what happens

 

[frizbeedog]

.....My guess is you may have a loose connection somewhere on the grounded conductor simply because that is the common link between the circuits. If the panel is a sub I would check the grounded conductor on the feeder on both ends.

My first thoughts as well when he mentioned multiwires.

 

[TwinCitySparky]

Amprobe

Amprobe

If tightening the grounded conductor does not show results, I would take an amp reading on both circuits under full load to guarantee nothing else was accidentally tied into this circuit. Somethings just not right there...