Network "locks up" when the AC comes on in the building 2

[jimbob1120]

We have a server running through a Smart-UPS 1400. Often when the AC comes on, the workstations will "lock-up" and loose their connections to the various network drives. After a few minutes, the server will resotre the connections. I am wondering what I can do to eliminate this problem. THanks for any responses.

 

[dkediger]

Is the server actually going down? Are there any events recorded by PowerChute - if its used?

I would suspect a hub/switch might be losing power as the AC comes on - that or a number of the network cables are in close proximity to the power line feeding the AC unit and are getting garbled with interference until the AC power draw stabilizes.

 

[technome]

If your using cat5, power line interference will not be an issue due to the interference canceling ability of the wire twist, if other than Cat5, this could be a problem.
Agree with Dkediger about about switches/hubs/broadband modems/printer etc which are directly attached to the NET if they are not on UPSs. Your workstations could be causing the connections to drop, assuming they are also not on UPS.

The building power supply is not adequate, most building are adequate when first built, but the power distribution system becomes over utilized with added loads, especially in building built before the 1960's. The way to correct this is major building rewiring, which I doubt is going to happen. Another possibility is to have an electrician add power factor correcting a.c capacitors, large ones, at your office feeder cables to correct poor power factor conditions ( you would need an electrically engineer to advise you). Another item, a constant voltage transformer to feed the office, rather expensive.
All in all, would be cheaper to have UPS units on all computers and devices. If this is your decision I would purchase refurbed APC units,with new batteries at about 1/3 the price, I purchase them all the time

 

[jimbob1120]

Thanks for the responses. The server does not actually go down. We are using Cat 5 cables. I have a network printer that is not on a UPS and possibilty one workstation without a UPS. I will get them both set up and we will see how it goes.

Thanks again for your help.

 

[technome]

I assumed from your writing tone your server remained fully functional.

I suspect your switch/hub or a print server device. As a test, during off hours with the workstations on, you could kill power to the switch/hub for a split second, and see if the problem duplicates. Would be best to have some network traffic for the test.

If you doubt your cat5 read my post from the link

http://www.tek-tips.com/viewthread.cfm?SQID=773806&SPID=583&newpid=583&page=1

Have seen very similar problems as yours, couple were in industrial plants. In one, every time a boiler blower (20hp) would kickin the Net would freeze, and the phone system would reset (even with a APC BBU on the PBX). At this site, they ended up running a new service feed to the offices along with a "soft start" control for the boiler blower.