Dimming Light On New Circuit - Electrical - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 01-06-2011, 10:56 AM   #1
Member
 
Join Date: Feb 2010
Location: South Seattle
Posts: 520
Rewards Points: 512
Default

dimming light on new circuit


We recently upgraded to a 200 amp breaker box and got a new overhead service wire from the street. We are slowly replacing all the knob & tube and redesigning the circuits room by room as we renovate our house. One of the bedrooms has been completely rewired and is on its own 15amp arc fault breaker. (The work was done with permits and inspections.) Here is my question: the coffee maker is definitely on a different circuit (knob and tube), yet when its heater element cycles on and off, the bedroom (romex) lights dim a little bit. Is that to be expected? It seems to me like there should be sufficient current to run both easily, but then again I am just learning about electricity. Thanks for any insights.

Advertisement

Windows is offline   Reply With Quote
Old 01-06-2011, 12:20 PM   #2
Member
 
Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 6,976
Rewards Points: 2,048
Default

dimming light on new circuit


You will need electricians' experience.

Measure the voltage at various places inside your main panel as the coffee maker switches on and off.

Including both the big lugs where the service wires come in and the service wires themselves.

We cannot rule out minor deficiencies in the power company pole transformer that cause noticeable voltage changes with not so large changes in current draw.

But we do want to check for possible loose connections between sub components in the panel.

Ideally you want to measure voltage at terminals just before and after the meter except you may not open up that box.

Advertisement

__________________
Forget super sized fries. The Washington Redskins could promote healthy eating with First Lady Obama by choosing a (red skinned) turnip for a mascot.
AllanJ is offline   Reply With Quote
The Following User Says Thank You to AllanJ For This Useful Post:
Windows (01-07-2011)
Old 01-06-2011, 04:51 PM   #3
Member
 
Join Date: Oct 2010
Location: Cairns Australia
Posts: 2,721
Rewards Points: 2,402
Default

dimming light on new circuit


How much does the load change the supplied voltage ?
A small change is ok !
But if it is significant, then a current limit is in action.
You can start by working backwards from the light.
Measure at all connections,
If you find a spot where the reduction is a lot less,
or non existant, then you have an indication were the problem lies.
But if you get to the supply lines and it is still there, then the
problem lies with the electrical supplier.

Quote:
Originally Posted by Windows View Post
We recently upgraded to a 200 amp breaker box and got a new overhead service wire from the street. We are slowly replacing all the knob & tube and redesigning the circuits room by room as we renovate our house. One of the bedrooms has been completely rewired and is on its own 15amp arc fault breaker. (The work was done with permits and inspections.) Here is my question: the coffee maker is definitely on a different circuit (knob and tube), yet when its heater element cycles on and off, the bedroom (romex) lights dim a little bit. Is that to be expected? It seems to me like there should be sufficient current to run both easily, but then again I am just learning about electricity. Thanks for any insights.
dmxtothemax is offline   Reply With Quote
The Following User Says Thank You to dmxtothemax For This Useful Post:
Windows (01-07-2011)
Old 01-06-2011, 04:57 PM   #4
Member
 
rditz's Avatar
 
Join Date: Jan 2011
Location: Lindsay, Ontario, Canada
Posts: 271
Rewards Points: 250
Default

dimming light on new circuit


when you are moving circuits, make sure you are balancing them across both poles.

if you have an electrician friend, he will have a clamping meter that you can put on either of the incoming feeds. read the current on each leg. turn on and off different circuits and see if it is balanced.

rod
rditz is offline   Reply With Quote
The Following User Says Thank You to rditz For This Useful Post:
Windows (01-07-2011)
Old 01-07-2011, 01:06 PM   #5
Member
 
Join Date: Feb 2010
Location: South Seattle
Posts: 520
Rewards Points: 512
Default

dimming light on new circuit


Quote:
Originally Posted by rditz View Post
when you are moving circuits, make sure you are balancing them across both poles.

if you have an electrician friend, he will have a clamping meter that you can put on either of the incoming feeds. read the current on each leg. turn on and off different circuits and see if it is balanced.

rod
The circuits are no where near balanced. When we installed the new breaker box we had an electrician transfer the circuits from the fuse box and he didn't spend a lot of time evening them out because rewiring is in the near future. Consequently, we have a couple of breakers virtually running the whole house (minus major appliances) and others with only one receptacle. Can this imbalance be responsible for the light dimming?
Windows is offline   Reply With Quote
Old 01-07-2011, 01:50 PM   #6
Member
 
Join Date: Dec 2009
Location: Springfield OH
Posts: 768
Rewards Points: 500
Default

dimming light on new circuit


I have been amazed at the various forums threads on the value (or lack thereof) in the balancing of the demand on your electrical legs. Regardless, I have trouble believing that this would, by itself, cause a drop in voltage caused by demand surge.
oberkc is offline   Reply With Quote
Old 01-07-2011, 02:16 PM   #7
Member
 
rditz's Avatar
 
Join Date: Jan 2011
Location: Lindsay, Ontario, Canada
Posts: 271
Rewards Points: 250
Default

dimming light on new circuit


i don't profess to be an electrician, but it does stand to reason that you want to balance the poles for an even draw across each.

what is the value of having a draw of 70a/30a for example.

there are two things that are obvious to me with the original post... 1) the coffee maker is on the same pole as the bedroom lights. 2) the coffee maker is drawing enough load when the heater element comes on to dim the lights enough to be noticed.

by balancing the loads across the two poles, you are can effectively arrange higher draw items evenly so that two or more high draw loads are not switching on and off accummulatively causing a larger single spike than if they were balanced.

just my thoughts on it...

Advertisement

rditz is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to diagnose gas valve problems Nestor_Kelebay How To Guides 28 10-30-2013 05:19 PM
Wiring Size Calculations for New Service CorinthWest Electrical 7 12-07-2010 12:36 PM
Light switch vacancy detector, on two switch circuit sheslostcontrol Electrical 4 10-28-2010 02:55 PM
House light dimming Part II, had Power company come out ibjames Electrical 9 10-22-2010 10:35 PM
Resource for understanding gas valve? darsunt HVAC 19 02-04-2009 12:08 AM




Top of Page | View New Posts