[c-nsp] Multiple power supply failures. Advise needed

[Robert Johnson]

Coming from an electrical engineer:
Before doing anything else, you need to get someone out there with a
recording oscilloscope to verify the input power to your equipment. This is
the best way to ensure that you are getting the proper waveform, and that
your power is free from transients and sags. A normal managed UPS will not
be able to pick up infrequent spikes, harmonic distortion, etc. These are
all single phase 120 volt circuits, right?

Grounding is unlikely to be the problem. As previously mentioned, the safety
ground on the equipment power supply bonds the equipment chassis to the
facility ground. This is adequate in a typical data environment that is not
in a high lightning exposure zone. If you were in a telephone CO, a site
with a communications tower, etc., then it would be worth your while to make
sure that each piece of equipment and metal hardware was bonded back to the
MGB. But based on the information you've given here, I don't think this is
relevant to your power supplies blowing up.

I would go ahead and put some double sided tape on the air intakes for your
equipment. After a few days, peel the tape off and take a look at it using a
microscope or magnifying glass and inspect for metal particles.

Robert

On Wed, Sep 2, 2009 at 11:08 AM, Michael Ulitskiy <mulitskiy at acedsl.com>wrote:

> What about the fact that most (if not all) power supplies have independent
> sucking fan
> and that power supply air flow is separate from the system board flow.
>
> Plus all system board I saw are covered with some insulating coating.
> I've never pulled apart a modern power supply. I'd expect them to have
> something like that too, but who knows?
> Plus since PSU is the only part that's dealing with high voltages I expect
> it to be more sensitive
> to momentary shorts. Am I wrong?
>
> I'm expecting report for provider ordered unintrusive power monitoring.
> I'm almost positive they won't find anything, though.
> I'm still looking for advice on independent power analysis source in New
> York, NY if anyone has this kind of experience.
> Thanks,
>
> Michael
>
> On Wednesday 02 September 2009 10:29:07 am Randy McAnally wrote:
> > Plain old dust wouldn't be so picky...it has to be ingested past the
> system
> > board before it hits the power supply in most cases.  System boards are
> WAY
> > more sensitive to this kind of thing.
> >
> > The fact you have ONLY PSU's failing still makes me think you have power
> issues.
> >
> > --
> > Randy
> > www.FastServ.com
> >
> > ---------- Original Message -----------
> > From: Michael Ulitskiy <mulitskiy at acedsl.com>
> > To: "Randy McAnally" <rsm at fast-serv.com>
> > Cc: "Scott Granados" <gsgranados at comcast.net>, "Seth Mattinen"
> > <sethm at rollernet.us>, cisco-nsp at puck.nether.net
> > Sent: Tue, 1 Sep 2009 23:21:23 -0400
> > Subject: Re: [c-nsp] Multiple power supply failures. Advise needed
> >
> > > This is my main suspect now. They are doing work in the facility.
> > > Not heavy construction, but they do install cages and cabinets for
> > > new tenants and they're definitely using tools that  produce metal
> dust.
> > > My theory is that because of we've been the 1st customer who moved
> > > into that facility we've been collecting that metal dust for longest
> > > and so we're having a lot of problems with our equipment. To my
> > > knowledge none of our neighbors are having the same problem, but
> > > none of them have been in the place long enough. So the question
> > > remains: is there any way to fight it/protect from it except from
> > > going through the huge-huge-huge headache of undertaking another move?
> > >
> > > Michael
> > >
> > > On Tuesday 01 September 2009 08:48:38 pm Randy McAnally wrote:
> > > > He mentioned he was one of the first customers in the colo so
> > > > this might be a possibility
> > > >
> > > > --
> > > > Randy
> > > >
> > > > ---------- Original Message -----------
> > > > From: "Scott Granados" <gsgranados at comcast.net>
> > > > To: "Seth Mattinen" <sethm at rollernet.us>, "Michael Ulitskiy"
> > > > <mulitskiy at acedsl.com>
> > > > Cc: cisco-nsp at puck.nether.net
> > > > Sent: Tue, 1 Sep 2009 17:35:34 -0700
> > > > Subject: Re: [c-nsp] Multiple power supply failures. Advise needed
> > > >
> > > > > Also make sure that the provider isn't doing work in the facility.
> > > > >  I'll never forget going to an L3 datacenter and arriving to find
> > > > > workmen in the overhead grinding away and dropping dust and who
> > > > > knows what else in to all the racks below including a rack of Netra
> > > > > T1's that promptly sucked in the dust and kicked out power
> > > > > supplies.;)  It was definitely metal shavings because they were
> > > > > using a grinding type tool up in  the over head frames.
> > > > >
> > > >
> > > >
> > ------- End of Original Message -------
> >
> >
>
>
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