Electrically isolating network hardware from dehumidifier: isolation transformer or line conditioner

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Hi. I have a dehumidifier plugged into the same electrical outlet as my
DSL router and wireless router. I want to electrically isolate the DSL
and wireless units from the on/off switching of the dehumidifier. The
dehumidifier has a big electric motor inside of it, and I've read that
the on/off action of that motor kicks electrical garbage backwards into
the line and can affect my electronics.

I've narrowed my choices down to either an isolation transformer:

http://www.tripplite.com/products/product.cfm?productID=227

or a line conditioner:

http://www.tripplite.com/products/product.cfm?productID=208

The models I picked out cost about the same. It looks like they cover
most of the same ground, but not being an electrician, I'm not
completely sure. Which do you recommend?

Thanks.
Roger Carlson

 

[Bennett Price]

Hi. I have a dehumidifier plugged into the same electrical outlet as my
DSL router and wireless router. I want to electrically isolate the DSL
and wireless units from the on/off switching of the dehumidifier. The
dehumidifier has a big electric motor inside of it, and I've read that
the on/off action of that motor kicks electrical garbage backwards into
the line and can affect my electronics.

I've narrowed my choices down to either an isolation transformer:

http://www.tripplite.com/products/product.cfm?productID=227

or a line conditioner:

http://www.tripplite.com/products/product.cfm?productID=208

The models I picked out cost about the same. It looks like they cover
most of the same ground, but not being an electrician, I'm not
completely sure. Which do you recommend?

Thanks.
Roger Carlson

The isolation xformer won't help. The line conditioner will but you
want to plug your electronics into it, not the dehumidifier - this means
you can buy a much much smaller line conditioner.

But I would do two things first. 1) See if you actually have a problem.
The electronics gear is likely to do just fine without any extra gizmos.
2) See if you can run the dehumidifier from another socket or circuit in
the house.

 

[Charles Schuler]

Hi. I have a dehumidifier plugged into the same electrical outlet as my
DSL router and wireless router. I want to electrically isolate the DSL
and wireless units from the on/off switching of the dehumidifier. The
dehumidifier has a big electric motor inside of it, and I've read that
the on/off action of that motor kicks electrical garbage backwards into
the line and can affect my electronics.

You most likely do not need any isolation. Your routers have power supplies
with big capacitors that will absorb reasonable transients. I lean toward
protecting the entire building or home with a transient suppressor at the
main power panel.

 

[Al Dykes]

You most likely do not need any isolation. Your routers have power supplies
with big capacitors that will absorb reasonable transients. I lean toward
protecting the entire building or home with a transient suppressor at the
main power panel.

it doesn't hurt to put the smallest name-brand UPS you can lay your
hands on in front of the DSL modem and router. I was able to use the
internet with my laptop for the entire 24 hours of the last big
blackout because that's how I was wired.

I had a *big* ups for my desktop system, which I shut down as soon as
the power quit. I ran the laptop and the DSL connection off the big
UPS for the next day, easily.

Nothing, short of a direct lightning hit, that happens to your DSL
router can be propagated to your PC or any other LAN devices.

 

[Peter]

Hi Roger,

I've narrowed my choices down to either an isolation transformer:

http://www.tripplite.com/products/product.cfm?productID=227

or a line conditioner:

http://www.tripplite.com/products/product.cfm?productID=208

I had a simlar problem with my 3 x PC's at my home, long tern stabilty
issues relating to AC supply "noise". An AC Power Filter removed the
major part of the noise (spikes, surges, etc) from the line, but not
the "short term" (.5 - 2 second) "hits". Plus after 5 years the Power
Filter stopped being effective and actually resutlerd in premature
failure of 2 x Power supplies in 2 machines util I worked out what was
going on..

I then invested in a small UPS and all 3 amchines have been perfect
(IE 100%) since then (justover 3 years so far). Yes, I have had AC
outages longer than the battery life (~25 mins), but anything less has
been 100% convered. I can definately recommend a good small UPS
(~500VA capacity per PC). The hard part is sizing the unit for your
particular environment.

Good luck...............pk.

 

[default]

Hi. I have a dehumidifier plugged into the same electrical outlet as my
DSL router and wireless router. I want to electrically isolate the DSL
and wireless units from the on/off switching of the dehumidifier. The
dehumidifier has a big electric motor inside of it, and I've read that
the on/off action of that motor kicks electrical garbage backwards into
the line and can affect my electronics.

I've narrowed my choices down to either an isolation transformer:

http://www.tripplite.com/products/product.cfm?productID=227

or a line conditioner:

http://www.tripplite.com/products/product.cfm?productID=208

The models I picked out cost about the same. It looks like they cover
most of the same ground, but not being an electrician, I'm not
completely sure. Which do you recommend?

Thanks.
Roger Carlson

IF YOU HAVE A PROBLEM :

A filter on the offending gear will do more at far less cost than all
the gear you hang on the router's power supply.

My electric range was talking to my audio modem (different outlets of
course, but parallel wire runs, same electrical service)

No amount of filtering on the phone line or modem supply (external
modem) would fix it. For years I had to shut down the modem while
cooking. - and I have a lot of experience in the field.

I fixed it by winding a simple choke and putting the choke and a
couple of capacitors across the line inside the stove. I had to do it
that way because I couldn't find a ready made filter for the stove
(too high current)

Try a power line filter on the dehumidifier. Not a "surge suppressor"
Surge suppressors are only good for removing damaging power line
spikes - L-C , Inductor/capacitor filters take out the hash the surge
suppressor won't.

Likewise a simple resistor capacitor "snubber" added across a switch
will kill a lot of the noise. 100 ohm 1/2 watt resistor in series
with a .1 ufd / 250 volts AC capacitor, wired across the switch
contacts in the dehumidifier will stop a lot of hash because it
absorbs most of the inductive spark when the switch opens.

An ounce of filtering on the noise generating apparatus will do more
than any amount on the noise receiving apparatus.

An isolation transformer is not likely to do much good unless it is
"box shielded." A very expensive, but very effective noise
eliminating winding technique. The primary and secondary windings
both have electrostatic shields around the entire winding. Each
shield is insulated, brought out separately, and grounded to different
points.

I worked at a power supply manufacterer where we made a few custom
wound box shielded transformers - with the amount of effort that goes
into one, I'd be surprised to find a production commercial unit for
any reasonable cost.