Well, I got a little more money than I was expecting to this week, so
last night I went out and bought some more tools that I thought I'd be
using a lot... I've realized that there are a few tools that I've
always had access to but never bought for myself, that now I have to buy
because I have my own place and I'd like to be able to do work here...
anyway, I got myself a new Sawzall and a 4-1/2" angle grinder, among
other things. This AM I just plugged them in and ran them to make sure
they worked before throwing out the packaging. The girlie yelled down
from upstairs, "you know, when you turn that on, the lights dim up
here..." WTF? I was using them in a 20A kitchen counter receptacle
which has nothing else on the circuit. The 15A lighting circuit for
upstairs is completely separate (and may or may not be on the same
phase, I don't remember.) Is this an issue, and what could cause it?
I'm guessing poor neutral connection at the panel?
Granted I did buy a real honest-to-god Milwaukee Sawzall and a good
Milwaukee angle grinder, not some cheap lightweight crap, but I think
both are rated at 10A which I would assume a 12/2 branch circuit would
handle no problem.
replace "fly" with "com" to reply.
Other factors come in play. Think of the electric supply as a water supply.
There is only so many watts coming into the house. When there is a surge at
one outlet, there will be a drop at another. Some tools take quite a bit of
power to start up, well beyond the 10A running load. Sort of the same as
when you are in the shower and the dishwasher suddenly fills.
At the same time you started up that grinder, the refrigerator, heater, TV,
lights, etc were using some of the available power so a surge was very
I agree with Ed. Frankly I would be more worried if they got brighter.
That would be a problem and it does happen.
The question is how much. Within reason it is normal. It also might be
a good indication that your home wiring including the supply my be
undersized for today's use. How old is your home?
It may be normal, but it wouldn't hurt to spend some time going around
the house pulling outlets and switches and tightening connections along
with the connections in the main panel and any sub panels. It may be a
bit tedious, but you might find some developing problems.
To answer some other posters, the house was built in the late 40's but
currently has a 200A service. And I *am* currently systematically
going through the house replacing all the receptacles, switches, etc.
and rectifying problems as I find them. I just thought it odd that
this would cause dimming on circuits other than the branch circuit that
I was plugged into, seeing as there's that big fatty cable feeding the
Thats what I was thinking....
Also, since its a kitchen outlet, was a refrig running at the same
Also, is the same neutral being used for the two circuits that were
invloved? If YES, carefully check that neutral connection.
Finally, install a completely separate circuit for you workshop tools.
Of course we all know that those portavble tools get used in other
parts of the house too.
One last thought. Is the light that dimmed connected to a dimmer?
Those dimmers are often sensitive to voltage changes, and the "dim
effect" is more noticable than on a common "switch only' circuit. I
have seen this happen.....
If you got a meter, start watching the voltage in your house. Hook
that meter to the upstairs light, and turn on your power tool in the
same outlet you had it. Have the wife watch the meter, etc....
If your transformer is marginal, ALL lights in the house should dim.
But then too, it depends on what other neighbor houses (on the same
xformer) had running at the time too. They do sell meters that record
voltages, but they are costly.
Tell me about it. My neighbor's central a/c makes my lights dim and
reset every time it kicks on. :( I think the whole bunch of us on the
get together and turn on our dryers to get a new xformer. :D
That appliance draws trivial power. However wiring has a defect so
significant that even light bulbs are affected. You now have a
diagnostic tool to find that defective wiring - light bulb and Sawzall.
Your first discovery is electrical wiring connection between that
upstairs light and Sawzall's AC receptacle. Are they on same circuit
breaker? If yes, then how are they connected? If not, how are those
circuit breakers related?
No one can provide a useful answer without circuit descriptions and
further tests. But this you do know. That Sawzall and grinder consume
minimal and irrelevant power. Even a smallest 15 amp circuit should not
cause light bulb dimming. If those small power consumers affect light
bulb intensity, then you have a potentially serious wiring problem.
Neutral wire is only one potential reason for failure. But then if
Sawzall caused light bulb intensity change, then so did washer, dryer,
furnace, dishwasher, etc. Needed: more facts including household
One trick: as each circuit breaker is identified, then write that
circuit breaker number on back of receptacle cover plate. Useful
information for solving future problems faster.
Nate Nagel wrote:
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