[Year 12 IPM] OT: Computer Room Power Issue - I'm desperate!!!

[Andrew Shortell]

Hi Kim

We had that EXACT problem at MacRob in a brand new building

The power supplies in the computers had leakage (very small)

We upgraded the RCDs from 30milliamps to 100milliamps

No more problem



Andrew Shortell
Braemar College 


-----Original Message-----
From: ipm-bounces at edulists.com.au [mailto:ipm-bounces at edulists.com.au]
On Behalf Of kgration at myrtlefordsc.vic.edu.au
Sent: Monday, 27 March 2006 8:15 PM
To: ipm at edulists.com.au
Subject: [Year 12 IPM] OT: Computer Room Power Issue - I'm desperate!!!

Hi there folks,

Thought I'd pick your brains and send out a general query to you all
about the following rather difficult and painful situation:

Over Christmas we had two new computer rooms cabled with both data and
power outlets by Nilsen (a reputable company).

Upon completion of the project, it was found that one of the rooms is
fine but the other one has a major issue on the power side of things.

The two rooms are provided with power from two separate switchboards
(the one that is working fine is from the main switch, the problematic
one from a sub-switch connected to this main). This sub-switch has
numerous other problem-free circuits running from.

Both rooms have Acer PCs (different models in both rooms) and three
combo RCD (safety switch)/circuit-breakers providing power to them. The
problematic room has Veriton 5500's (16), Veriton 5100's (3) and the
remainder are Veriton 5600G's (2) = total 0fr 21 PCs. i.e. 7 PCs are
connected to each circuit-breaker (not a particularly huge number).

The problem that we are having basically is that one or more of the
circuit-breakers keeps tripping whilst classes are using this room. It
doesn't seem to happen when the PCs are on but not in use and has not
been affecting the same circuit-breaker every time (i.e. not consistent
and very unpredictable).

Nilsen's wiring has been checked by our local electrician and by an
electrical inspector and has been found to be fine.

So far (with our trusty local electrician) we have tried the following
to no avail:
- upgrading the circuit-breakers from 16 to 20 amps
- installing three RCDs (safety switches) in place of the three
circuit-breakers and one RCD (that was in the original installation)
- manually tested turning on and off various combinations of computers
connected to each of the three RCDs etc.
- tested the RCDs (all are OK and within the expected limits)
- had an Acer tech out (no real help at all)
- megad (I assume that's how you spell it!) the circuit (nothing
obviously wrong)
- directly swapping the full complement of computers over between the
two rooms (nothing unusual happened)
- balancing the phases across the three RCDs (i.e. three phase power)

Based on what we have observed so far it would appear that the
cummulative total of the current leakage across the power supplies is
the most likely cause of the problem . . . it is proving whether this is
the case or not that is currently a real problem!


Has anyone experienced difficulties anything remotely like this? How did
you resolve the problem? Has anyone else had power issues specifically
with Veriton 5500's? Any ideas/suggestions are not too ridiculous at the
moment as we are in a real bind and are fast running out of things to
try!

If you could email responses directly to me rather than to the list
that'd be fine and would spare others from having to read this already
sizeable story again!

Cheers,

Kim

---
Kim Gration
ICT Manager
Myrtleford Secondary College
http://www.myrtlefordsc.vic.edu.au
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