Electrical – Can the apartment’s electricity harm the computer? Is there an easy way to test the electricity


I live in a (rented, 1980 built) row townhouse in the USA with slightly suspect electricity:

  • A few of the outlets and light switches in the house (in various rooms) don't work at all. (Even allowing for some switched outlets.)
  • My five year old desktop computer on the ground floor developed a bad power supply a few months after moving in. (After a cross-country trip in a moving van, and it is an old computer.)
  • Plugging anything into one outlet on the ground floor often shorts out the rest of the stuff in the room. (We avoid using this outlet!)
  • A 5-6 year old laptop's power adapter doesn't work on the ground floor, but does work upstairs. (A newer laptop works both upstairs and downstairs, so it's possibly a bad power supply on the old laptop.)

Given that the computers in question are 5-6 years old, and we jostled them across the country moving, it's entirely possible that their time had/has come and they need to be replaced. However, before I buy and plug in a new desktop (or keep using my other newish computer) with this potentially suspect power, am I right to be concerned about it? Could the damage have been caused by the times we've shorted out the downstairs room? Or maybe slowly over time by bad power?

If I had a multimeter or some other test device, could I test my outlets and/or electricity? Do I need to call an electrician? Should I just assume that my computer died of old age and replace it without worrying that the new one will meet a similar fate?

Best Answer

Yikes, it sure sounds like you have several issues with your electical wiring there. I won't speak too much to your power supply issue, but really think you should invest in a UPS to mitigate any power related damages to your equipment.

Now lets correct a few mistakes in the previous answer.

The 120VAC legs of your electrical service are supplied by two separate hot feeds from the power company. The neutral is not there to split the 220VAC, but rather to supply a return path to the service panel and ultimately earth ground.

The neutral should be at the same potential as ground. An open neutral is checked by measuring neutral to ground, if line voltage appears, then in fact the neutral path to ground is open. Unless you have a situation where both 120VAC legs are in contact with one hot connection, you cannot produce more than 120VAC on any open neutral. If you were to see 140VAC on any hot to ground or neutral, or neutral to ground, then you have some serious problems and time to call the landlord before you fry all your lights, appliances, and electronics. This situation is very rare, and I don't think it is your problem. Your problem sounds more like a bad connection, either hot or neutral in some device that feeds your downstairs outlets.

This can be a frustrating and time consuming job to track down this type of problem. It may involve pulling several devices out of the boxes and testing voltages with the power on, and also testing conductivity with the POWER OFF. Unless you have the experience and you feel very comfortable working on hot wiring, I'd suggest you have the landlord call in an electrician ASAP.