cruzer3244
Member
on the ups system do you have to have a shunt breaker on the primary side,and the load side.this is in case of a fire,so the fireman can kill all power.
shunt switch computer room.
- Thread starter cruzer3244
- Start date
- Status
It depends on how long it takes the firemen to get there and how much load is on the U.P.S.
I thought it was neede because of the fire suppression system spraying all over the electronic servers.
Rick
Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
Are you saying the UPS is part of a computer room, as in Article 645?
cruzer3244
Member
shunt switch
shunt switch
Yes its inside the room.
shunt switch
Yes its inside the room.
cruzer3244
Member
yes its inside the room.
- Location
- Massachusetts
Most if not all hardwired UPS will have built in terminals for shut down from an external EPO.
cruzer3244
Member
that EPO should kill primarv and battery. write
Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
I believe you are talking about an EPO. Take a look at Article 645, there is a lot to read about, not just the EPO.
- Location
- Massachusetts
Killing the supply to a UPS will not stop it's output, that is why you would use the on board terminals to get it done.
cruzer3244
Member
I understand that,what I need to know is do I need a shunt breaker for the line side. thanks
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
I have seen so many UPS's improperly done by killing the line side feeding the UPS, as iwire said you should have an input for the EPO switch(s) in the UPS. Adding a shunt trip past that would be redundant, and still would leave the UPS unit running, though would kill the load. The UPS unit should be shut down also, it may be the piece of equipment thats on fire!
brother
Senior Member
Ive always wondered about this. Ive seen where these server/computer rooms would have these epo's at the door and even if its pushed the ups keeps the server up. Ive also seen where these epo's would not shut down the air conditioning unit, or close the fire dampers!!
Just done wrong.
Just done wrong.
Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
It was either improperly installed or the room was not a true Art 645 room.
cruzer3244
Member
shunt switch
shunt switch
I just like to know,if there was a fire in the room shouldn't the EPO SWITCH kill all power in the room.
shunt switch
I just like to know,if there was a fire in the room shouldn't the EPO SWITCH kill all power in the room.
brother
Senior Member
Yes it should.
- Location
- Massachusetts
It is not that easy.
First the NEC does not really require an EPO at all. You can have a room full of computers, servers UPS systems and not have an EPO.
However if you have an EPO and satisfy all the other items listed in 645.10 then the NEC allows you to do more of the power wiring in the room with flexible cord.
If you chose to go the EPO route then the EPO must shut down the power to the electronic equipment. The lighting power can stay on.
I can't stress enough that if you really need to know about this pick up the NEC and read Article 645, it is not long but it could save you a lot of grief.
dbuckley
Senior Member
- Location
- Canterbury, New Zealand
And just to re-iterate - all trips must be shunt trips, not series hold trips. A computer EPO is a system you want to fail dangerous, not fail safe.
brian john
Senior Member
- Location
- Kilmarnock, Va
- Occupation
- Retired after 52 years in the trade.
In my experience the only time this is used is by Cleaning people, electricians and those that say what is this for/ In 30 some years of doing data centers have seen maybe 20-30 EPO's activated all were accidental.
paul
Senior Member
- Location
- Snohomish, WA
This is something that I went through about a year ago. I also did some research on it and you cannot find the DPO cord that is listed for use under the floors. After several phone calls to those in the know and posting on this board, I came to the conclusion that this section needs to be re-written.
We ended up running EMT under the floor for everything for our customer and placing 4000 wiremold on the racks. They preferred how we did it and were glad to get rid of the spaghetti mess of sealtite from underneath the floor.
Back to the subject, though. As Bob stated, EPO's are required only under the circumstances listed in Articl 645. In the job I mentioned above, I convinced them to get rid of the existing EPO's when we replaced all their PDU's and their UPS system. The IT guys were happy to get rid of them. But even they took a bit of persuading because they thought it was required in ALL server rooms.
Short version..
Following article 645 = more flexibility for wiring methods, but need EPO.
Not following article 645 = following section 300 for wiring methods no EPO required.
weressl
Esteemed Member
That is correct, however you would still want to kill the power coming to the UPS, so use the EPO contacts on the aux. terminal strip to trip the UPS and use a shunt trip on each breaker(Normal and Bypass) feeding the UPS .
- Status