Lights dim when AC comes on

ttownJune 19, 2011

We have a house that was built in 1960, and had it rewired in 2005 because of the old wiring. Lately the lights have started dimming a little when the AC unit kicks on. What could cause this and should it be a concern

Thank you for reporting this comment. Undo

It is actually not that abnormal, but if it is NEW it may indicate the AC is taking longer to start up.

When induction motors like the one in the AC compressor outside start up they pull a VERY large starting current.
Often 2-3 times there running current.

If you want to see how much difference there is between starting and running, there should be a running current (often marker FLA, for Full Load Amps) and a Locker Rotor Amps (LRA) that indicate show high the starting surge can go.

If it is new it may indicate you need to start saving to replace the condenser (and possibly the evaporator inside so they match up correctly).

    Bookmark   June 19, 2011 at 11:30AM
Thank you for reporting this comment. Undo

Call your POCO and tell them you have flickering lights.
They will, (should), put a recorder on at the meter box.
If the voltage dips show up there, then the problem is
with their equipment and they should fix it. There
will be no charge for this from them. If the voltage dips
don't show up where the power comes to the house, (meter box), then the problem is in your equipment.

    Bookmark   June 20, 2011 at 7:53AM
Sign Up to comment
More Discussions
Please Critique Low-Volt (Home Automation) Plan/Proposal
GW/Houzz Community, As always, I want to thank this...
Andrew K.
Dryer power cord next to vent
My contractor is enlarging the dryer vent hole in the...
Need to Understand GFCI Requirements.
I posted this in the remodeling section, but I think...
Outdoor subpanel as AC disconnect
Can we use an outdoor subpanel as an AC disconnect?...
Power to shed
Looking to run one 20 amp circuit to my shed and I'm...
Sponsored Products
Uttermost Tilton Light Gray Ceramic Table Lamp
Beyond Stores
Progress Lighting 8 In. Pro-Optic Black Baffle Trim P8117-31
$68.85 | Home Depot
Delphine Coffee Table - BRASS/LT. BLUE
$1,999.00 | Horchow
Zephyr 48W in. Trapeze Island Range Hood - CTP-E48BSX
Meridian Row Light - Four Lights
Signature Hardware
Wharton Wall Sconce by Currey & Company
$500.00 | Lumens
Minka Lavery Transitional Large Pendant
Mercury Glass Candlestick Accent Lamp Base
Cost Plus World Market
© 2015 Houzz Inc. Houzz® The new way to design your home™