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Joined: Dec 2012
Posts: 1
Ashton Offline OP
New Member
Hello all, new member.

I work with low voltage, FOH Audio, Video, and build Computers and Networks. I'm surrounded by Electrical Engineers who I bounce unusual situations off but this one has everyone baffled.

Recently moved to a new house. During tour of house, I failed to notice that the power outlets were mostly 2 prong. The house I was living in before had 3 prong outlets, although they weren't acting as a ground they were just replaced by someone prior.

After moving in, I set up my home office. I have a 1300 Watt APC UPS plugged into a 2 prong to 3 prong adapter and I screwed the center screw around the metal tab on the adapter. Plugged in my PC to the UPS and all worked fine.

I left the room, came back and dead computer. Diagnosed what had died and identified the power supply, motherboard, 1 set of triple buffer ram, external blu-ray drive. Several months later after I RMA'd all those components, an SSD Drive died.

When I was disassembling the computer I noticed that the ground fault indicator light on the UPS wasn't on... Also, it wasn't kicking in when the circuit was tripped by an iron in another room.

I then realized that the UPS's Ground Fault Indicator Light wasn't on. The UPS was getting a ground from the Ethernet, cable Coax, and another PC via a very strange path.

60 Days ago, I received a replacement 1500 Watt UPS. Friday I noticed three short whole house power drops. My PC was fine and protected by the UPS. Saturday, I was in another room when I heard this, "POP, POP, POP!" from my office. I checked and the power supply smelled of electrical fire.

I have a Zinsco Panel in the house and contacted an Electrical Contractor and was told it will only get worse. The landlord can't afford to replace the electrical I fear, but I need to protect what I can for now until my lawyer can resolve this.

Any electricians out there know how my UPS could be bypassed to cause this failure?

Power Company came out and said there was corrosion on the neutral line and they'd replace the connectors but that the problem was on the inside.

Everybody here is stumped and my PC has not been the only casualty.

Thanks for any info, it may be helpful for my attorney and MGMT company.

Joined: Jan 2005
Posts: 5,457
Likes: 3
Cat Servant
You can afford all these neat toys, you can afford a lawyer .... but you can't afford to rent a better place?

Vote with your feet, man.

Joined: Apr 2002
Posts: 7,388
Likes: 7
The guy to comment on this is Gfretwell. He is the resident computer maven.

IMHO, you need an Electrical Contractor to install a new service & panel, and correct your ground issues.

Renos comment, although a little blunt, may be the way to go.

Joined: Jul 2004
Posts: 9,950
Likes: 34
In this case I would just start with an electrician. I think if it was my house I would do a service upgrade or at least replace the panel.
If this is a rental the fix may be to run a new circuit into the computer room with a grounded wiring method. Strange things happen when there is no ground present and your system goes looking for one through the phone or cable line.
The next thing is to look at the Dmarks for the other services to be sure they are grounded to your electrical system grounding electrode. You do not want to see separate grounding electrode systems. Again any ground shift will show up in your computer where the different systems come together.

Greg Fretwell
Joined: Feb 2004
Posts: 1,438
Power Company came out and said there was corrosion on the neutral line and they'd replace the connectors but that the problem was on the inside.

This totally stinks of a loose/corroded neutral causing voltage unbalance on a multiwire circuit.. This could cause one leg of the circuit to potentially see >200V, which would fry most 120V anything pretty quick.

1) Has the problem reoccurred since your power co. cleaned up their connections?
2) Was the other equipment which was damaged plugged into the same circuit? (You mentioned the breaker tripping while using an iron. Did you take notice of what all turned off when that occurred?)
3) Do you notice dimming lights or other voltage fluctuations for seemingly no reason?
4) What year was the home built? (to get an idea on possible wiring methods. Zinsco came to being in the mid 50's and died (not soon enough) in the early 80's)

Zinsco breakers are famous for not maintaining good contact with the busbar in the panel. They'll just kinda arc between the contact clips and the bus under load, the clips will expand due to heating from the poor connection and you'll lose all power on that specific breaker (or the half the house if it's a leg of the main). Once this happens, the contact clip will cool down as no load is passing through and eventually make contact again, essentially cycling. 240V equipment can cause eerie things to happen on the 120V side if you're losing a leg on your main circuit breaker.

I've replaced well over 100 Zinsco panels around So Cali... This being the #1 reason for at least 90% of them.

Joined: Oct 2000
Posts: 2,723
Likes: 1
Broom Pusher and
As Randy ("Lostazhell") mentioned, this issue smells of an open Common Grounded "Neutral" Conductor scenario.


Power Company came out and said there was corrosion on the neutral line and they'd replace the connectors but that the problem was on the inside.

I am beginning to believe that all POCO Representatives are "Programmed" to repeat this statement, when speaking to Customers during a Complaint Call.

Even if the Transformer fell off the Pole, right at the House of the Customer whom called in the Complaint, I bet the story would still be
"Outage Problem is on the Load Side of the KWH Meter"!!!

Sorry to rant!

--Scott (EE)

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

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