I need to put a centralized UPS in my business office. Do I need to
get into an expensive 3 phase unit? Or will the elecrical code allow
me to distribute the outlets from a less expensive 115v consumer UPS,
through existing conduit, (to orange outlets), to 3 separate offices?
The number of computers I need to protect can easily be handled by a
larger consumer unit. However my question is on the code legality of
distributing the UPS outlets back out to the 3 offices. I can esily
pull dedicated wires through the conduit. I would keep the UPS unit
in the electrical room by the mains.
It would seem to me that "less expensive consumer unit" and wiring an
appropriate size unit for 3 offices are mutually exclusive. Why not
just use a seperate consumer UPS in each office ? Aside from the
cost, the consumer units come with outlets built-in. How are you
going to then wire that in for distribution?
Another note, whatever you get, you surely don't need 3 phase, unless
you have 3 phase eqpt in those offices.
On Apr 24, 6:46 am, firstname.lastname@example.org wrote:
I meant 3 phase on the primary side of the UPS unit where the output
of the unit is a single phase inverter to 115v.
For hookup I was thinking of making extension cords out of 3/8 BX
cable and steel plugs. Those would go to a pull box. From the pull
box I would go into the subpanel just to pass-thru into the conduits.
UPS would be secured to the wall.
It is a commercial office condo unit with 3 phase main, but I have a
single phase subpanel for these offices (signage, parking lot, AC,
heat, etc is common and 3 phase). All the conduit from the subpanel
is 3/4 so there is plenty of room. I just dont know if it's ok to
distribute from a plug-type UPS unit, or if I have to look for a wire-
in unit (which I've had a hard time finding).
Yes, but I'd still have the issue of combining the electrical systems
unless I use a dedicated raceway. I think just getting a larger APC
or Triplite consumer unit and distributing with wiremold is the best
fit for this cost-wise. About 5000VA is all I need mostly to keep the
network LAN and servers up for a half hour or so, the desktops are
shut off at night. The unit I'm looking at has a built in web server
to check on its status remotely too. I'm not building a whole data
center but like the idea of being able to lock up the UPS centrally.
All the small data-center wire in units I've seen start above $5,000.
"to keep the network LAN and servers up for a half hour or so, the
desktops are shut off at night."
If you aren't trying to keep the desktops up, why not put the UPS, the
comms gear and servers in your electrical room, and pull cat5 (or 5e
or 6 or whatever) to the workspaces? Seems to me pulling data cable
to 3 offices is a better bet than running new AC lines. As a bonus,
you can keep people from monkeying with the servers!
You can "protect" the desktops with surge suppressors if they don't
require high availability.
On Apr 24, 4:38 pm, email@example.com wrote:
The desktops are already networked into the LAN, the servers and
network stuff is already locked up separately without a UPS. My
intention was to put a UPS with the secured servers, then install
orange outlets in 3 cubes for the desktops all hooked to the one
locked up UPS. I dont understand what you're suggesting. I'm just
trying to avoid having UPS hardware in the cubes if my locked up UPS
already has 3000 to 5000VA available and is secured.
To do this in an NEC compliant way, you'd need to install permanent
wiring between the server room and the cubes using a wiring method
appropriate for your building type. You can terminate the server room
end of each run with an inlet that will accept the female end of a
cord. Then you can use a short cord to connect the UPS outlets to the
There may be labeling requirements for the receptacles in the cubes to
indicate that they are powered by a source (the UPS) that will not be
shut down by the main breaker, I'm not sure about that. Another
possible issue is that these UPS powered repectacles couldn't be
disconnected without access to the UPS, which you indicated would be
kept locked. I don't know if that would be a problem.
The cheap units have cheap batteries (and a cheap battery charger) and the
result may be that when the "mains" go down, that may not carry the load
long enough even to safely shut down the system.
There are "code" provisions for "separately derived" power sources. It's
no big deal. The grounding and "bonding" rules still apply.
Three phase equipment is a good idea at higher power levels. If you are
talking of a "pure" UPS (rather than a system that does a quick transfer
from mains to inverter, a 3 phase input will reduce the cost and increase
the efficiency. On the output side, a reasonably balanced 3 phase system
can provide better results at the same cost.
If you really, really want to have secure data, you want a good and well
thought out UPS.
Note that "they" make PC power supplies that take in 48 volts DC. These
can be powered directly from a battery. For most data handlling a server
applications this might be the most cost effective approach. You still
would need a "traditional" UPS for the monitors but your "power glitches" of
a few second or even hours would not cause any data loss.
Code varies from location to location, so no one can answer your question
accurately. However, most codes do not allow different electrical systems in
the same conduit and electrical boxes. A UPS in most locations would count
as a separate electric system as it would be powered when the mains are cut
off and could present a problem if someone worked on the conduit after
turning the mains off or interconnected the two power systems. I think you
would have to install a separate conduit or wiremold raceway to carry UPS
I'm so used to pulling, I didn't even think of wiremold, that I know
would be up to code. I can easily come down into each office from the
drop ceiling and still keep the plug-type UPS unit(s) locked up in the
I first thought of buying 4 separate UPS units and lock up the one for
the LAN but decided against that, costs more.
I secure the servers and LAN equipment in a separate room, so since a
UPS is becoming an integral part of the network now, I want to secure
that too. The desktop computers are less important to have on the UPS
because no critical data is on them and shut down at night, but I
would still like UPS outlets available to the 3 office cubes. I
simply dont want the LAN or server hardware accessible to anyone but
me, same with the UPS its plugged into. The servers are up 24/7,
except when the new UPS does a controlled shutdown of the servers in
the event of a power outage.
That's not taking into account wiring per code. If you could get away
with snaking extension cords through existing conduits (you can't),
then it would probably be cheaper to go with a single central unit.
What you want requires wiring that conforms to National Electrical
Code. You imply you want to do it on the cheap which means electrical
Also, include proper ventilation for heat created by all that
You'll still need the conduit above the ceiling for commercial I think
for Code w/ the wiremold on exposed walls.
If it were me, I'd probably solve the connection problem by removing the
UPS plug and making that a permanent junction box instead if going that
But, depending on the arrangement and number, I'd agree it seems the
individual units might still be simpler/cheaper depending on just how
many there are that really need the UPS.
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