Are there powerstrips or surge protectors with TWO supply-side power cords?

I have a lot of computer equipment that needs to stay operational
24x7. It?s all connected to UPSs. I'd like to connect each UPS to a
device (which could be a powerstrip, surge protector, or similar) with
TWO power cords, so it can be plugged into TWO outlets (on two
different circuits), drawing power from cord "A", but using cord "B"
if "A" goes dead. This setup would allow me to move the equipment, if
I needed to, to a different office, or different floor, without
powering anything down: just move powercord "A", then "B", then "A"
again, etc. And it would also improve my everyday reliability, since
my equipment would continue to operate even if one of the circuits
failed.

Does anyone know where I could get a double-powercord device like what
I describe above?

Hello Bob_b_1999,

   Your idea, as you wrote it, (And as I understood it) would not
work, as it would be backfeeding power, creating one circuit from the
two.

  Your best bet would be to purchase an electrical redundancy
switching device, or STS. Since I don't know your needs, I will
suggest places for you to search out the exact device that will fit
your needs.


Genpro has various sizes.
http://www.genpropower.com/static_transfer.htm


GE STSs
http://www.geindustrial.com/cwc/products?pnlid=8&famid=46&catid=1661&id=sts&lang=en_US


Eaton STSs
http://www.powerware.com/UPS/Static_Transfer_Switch.asp


Cyberex
http://www.cyberex.com/members/super_switch/index.html

About Static Transfer Switches
http://www.mgeups.com/download/doc_intl/catalog/aft_uk.pdf


If none of the above are the correct product size, call Graybar. I
learned while in an IT program to count on these people. Talk to one
of their reps, who I'm sure can obtain just the right switch for you.
They may suggest a smaller type of switch, depending on the size of
your infrastructure.

Graybar
http://graybar.com/


Cyberguys, my favorite online source carries liberators that may help
you out as well, but NOT to supply power from two sources (No switch
in the liberators):
http://www.cyberguys.com/templates/SearchAll.asp?s=SA

Hope this helps! Please ask for an Answer Clarification, if not!

Regards, Crabcakes

Search Terms
============

electrical redundancy + IT + switches
STS switch

---

Clarification of Answer by crabcakes-ga on 17 May 2006 13:08 PDT

Hi again Bob,

   Did you try calling Cyberguys, or Graybar? Additionally, Black Box
will help you out. Here is one option for reducing the power used.
http://blackbox.com/files/productdetails/22543.PDF

http://blackbox.com/Catalog/Detail.aspx?cid=244,1309,1319&mid=272



   Don't you suppose that if one circuit went out that the other would
too? If the main power is off, no circuit will work. Do you often hace
a circuit blow? If so, you may need to install a larger breaker switch
in your circuit breaker box.


With a larger breaker, then you could use one of these:
http://blackbox.com/Catalog/Detail.aspx?cid=183&mid=3634


Maybe this kind of UPS would work to keep your PCs up!
http://blackbox.com/Catalog/Detail.aspx?cid=183,1324,1329&mid=127




Also expensive are these UPSs
http://blackbox.com/Catalog/Detail.aspx?cid=183,1324,1329&mid=3368

http://blackbox.com/Catalog/Detail.aspx?cid=183,1324,1329&mid=135

Regards, Crabcakes

While Crabcakes' answer wasn't exactly what I was looking for, it got
me close enough (and gave me the applicable terminology) that I was
able to find the appropriate device myself.

I agree with crabcakes-ga on this one. Whatever you do, don't wire up
something yourself in the way you described, for safety reasons.

Consider what would happen if you unplugged powercord B. Now the
voltage would be feeding through from powercord A, making the pins of
B electrically live.

There must be some kind of switchover device to make this work safely.

Well, yes Crabcake, these STS units would certainly do the job, but
they're extremely high-end! The first one I looked at sells for
$70,000, and all of them are multi-thousands. I was looking for
something in the couple-hundred range. This would seem feasible, since
one of our UNIX boxes, an IBM xseries 236, has two power cords (this
is what gave me the idea in the first place), and the entire system
sells for under $2K.

Would a portable generator/battery on a large cart with a ups seve for
moving equipment?

At least you could take it into the elevator live.  

Daisy chaining up an down the halls seems a lot of work. 

What is the maximum time they can be disconnect from the network?

Based on the leg up from Crabcakes, I found exactly what I was looking
for myself.  APC makes a line of them, selling for around $500: 
http://www.apc.com/products/family/index.cfm?id=14

"APC?s Rack Automatic Transfer Switch (ATS), also known as the
Redundant Switch, is a high availability switch that has two input
power cords, one for each AC line, which provide redundant power to
connected equipment. The Rack ATS is designed to supply power to the
connected load from a primary AC source. If that primary source
becomes unavailable for whatever reason, the Rack ATS will
automatically begin sourcing power from the secondary source. The
transfer time from one source to the other is seamless to the
connected equipment."