DIYbanter - View Single Post - APC hums (buzzes) when hair dryer is run in another room

Dan K

"BE" wrote in message
.. .
On 11/22/06 3:36 PM, in article
l, "Meat Plow"
wrote:

On Wed, 22 Nov 2006 20:27:10 +0000, BE Has Frothed:

We live in an 80+ year old house with wiring of similar vintage (I
assume).
All the computers are on UPS devices. My main computer is on an APC
Back-UPS
Pro 1000 with fresh batteries, which is certainly powerful enough to
handle
what's plugged into it. I will say that because there are no grounded
outlets in this house (except for one in the kitchen), the APC unit's
three-prong plug gets its 100v juice thanks to an adapter that ignores
the
ground prong.

My stepdaughter runs a blow dryer in her room and when she does, my APC
unit
makes a humming buzz sound for as long as the dryer is on. The unit
never
beeps (as it does when there's an outage or dip in power) - it just
makes
this buzzing humm.

Aside from whatever might be said of the lack of grounding (which cannot
be
helped), is this buzz indicating that any damage to the computer could
be
occurring?

Thanks,
Be

The APC should be grounded. You're sure it isn't switching to battery?

To the extent that such a switch would be indicated by the beeping of the
unit, I am positive that it is not.

I would love to be able to ground it properly, but this is not possible. I
figure it is better than running the computers themselves ungrounded and
subject to this house's "dirty" electricity. Since I lost a computer 7-8
years ago to the abuse this house's electricity inflicted upon its power
supply, I have made it a policy to have a UPS for everything I care about:
TV, wireless internet base station and DSL modem, plus all three of our
computers. I think it's better to have these UPS units ungrounded than not
at all.

Be

Ground the UPS (run a wire down the stairs to the kitchen if you have to)
and see if the buzz goes away when the hair dryer is on. If it does not,
then start looking elsewhere (temporarily try a different UPS?). If the
buzz does go away, then its a grounding problem...either find a UPS that
works better without a ground, figuring out how to ground the UPS
permanently, or forget it and see what happens.

Dan