Contact US

Log In

Come Join Us!

Are you a
Computer / IT professional?
Join Tek-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Tek-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Power protection question

Power protection question

Power protection question

Ok likely an easy question.I am looking to power my server room like this:
60a 3phase > apc 15kva ups > 3phase PDU1
60a 3phase > 3phase PDU2
Current load aprox 7500w

I am parinoid about the power going to PDU2 as it would come straight off the mains. Is there a surge supressor/filter or something that I can put in the middle to let me sleep better at night knowing my servers arnt going to get blown up by a random spike on the mains or my generator when it kicks in? (Unfortunately, I dont think my pdus have a surge supressors.)

RE: Power protection question

You absolutely should have surge suppression and filtering on the electrical supply to computer equipment. If you can't  budget for an UPS on PDU2, you should at least put surge protection on the power strips on the rack for the equipment. But check in advance how the equipment you're running without UPS protection will react to an un-scheduled shutdown or power drop. Another big UPS might be more cost effective than a bunch of smaller ones. Also consider Liebert power protection - that's what protects our data center. APC also has enterprise level products. Skimping on power protection is like saving money by having fewer lifeboats on the Titanic.

Fred Wagner


RE: Power protection question

All of the devices that are on PDU1 are also on PDU2 so they are UPS Protected on PDU1, if the power goes out they will stay up.

I do not wish to put a UPS on PDU2 because it costs more to aquire, maintain, and sucks 5% efficency off the top, not to mention another 5k btu of heat.

I am looking for a surge suppressor that will mount in line from the mains or a PDU that has one integrated but I seem to be having a hard time finding anything.  

RE: Power protection question

check out the 3000VA Power Conditioner at www.mcmaster.com -
they're about $2900 each, so getting 7500VA of coverage will cost you nearly $9000.  Are you sure that's a saving over going with UPS coverage on both ?
How about a UPS with dual feeds, so it can run off either of your PDU's - same idea as redundant power supplies in a server, just further back up the power chain ??

Fred Wagner


RE: Power protection question

Scroll a bit further down the page on the link I sent, there are rack mount power conditioners, with 14 outlets, 2400VA, for about $400. A couple of those would get the job done for you... but the original conundrum remains. You have a 50% chance that if a redundant power supply in a server fails, that it will be on the UPS-protected AC bus... or not. If both power supplies in a PC are not UPS protected, you really are NOT fully UPS protected....Where does your generator fit into your electrical plan ?

Fred Wagner


RE: Power protection question

Generator fits like this:
Mains-> Transfer switch and generator-> Main Breaker pannel. Its 125kva and backs up the office. Takes 1-2 seconds to kick in.

I had considered wiring both to the ups, and then having a straight wall outlet that I can connect one to as a very manual way of bypassing the UPS. (Should it have a major issue or need maintinance/replacing) And this is what I will do should I not find something that will work.

I know the protection isn't perfect, but the odds of a power supply going out on the ups psu and the power going out before I can either replace/swap the psu or make sure the working one is on the ups are just so low that I wont lose any sleep over it.

I was thinking something like: http://www.leviton.com/OA_HTML/ProductDetail.jsp?partnumber=52120-CM3&section=39957&minisite=10251

Might be sufficient.  

RE: Power protection question

The Leviton looks like a nice unit, rated for 30A. You mentioned in your first post that you're looking at a 60A source....
The Power Conditioners I pointed to earlier also handle voltage fluctuations (over and under) as well as suppressing surges. That can also be a nice feature if power becomes 'iffy' without actually failing. You know your local environment best.

Fred Wagner


RE: Power protection question

Thanks for the effort and assistance Fred, Actually I double checked my setup and we are looking at 30amp on the pdu and 60 amp on the UPS as it is oversized for later expansion. So I guess that is what I am looking for.


RE: Power protection question

Sounds like you've got it worked out. It's really nice when you get to build out an installation from scratch.  How about cooling ? got that covered too?

Fred Wagner


Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Tek-Tips Forums free from inappropriate posts.
The Tek-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Tek-Tips forums is a member-only feature.

Click Here to join Tek-Tips and talk with other members! Already a Member? Login

Close Box

Join Tek-Tips® Today!

Join your peers on the Internet's largest technical computer professional community.
It's easy to join and it's free.

Here's Why Members Love Tek-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close