My wiring frightens and confuses me

July 7, 2005 10:24 PM

My boyfriend and I live in a flat built in the '20s. We have reason to suspect that the outlets provide inconsistent amount of electrical current. Is there something we need to get for our computers to protect them?

You can't plug any appliances into some outlets in the house because they'll run at a snail's pace. Some outlets seem to do fine, but an additional problem is lack of outlets, which I know is very common in houses this old.

The main concern is the room where we have our computers. There is only one outlet in this room (two plugs). Into this outlet we have a daisy-chain of surge protectors and two computers with monitors, a TV, two lamps, some external HDs, musical equipment such as keyboard and mixers, and various things like cell-phone and battery chargers, etc. We've often marveled that we don't cause a brownout or blow a fuse in that room. In this same room, the wiring on a chandalier exploded shortly after we moved in. We found that it was the old-style fabric covered wire, and it basically crumbled when touched. I imagine that's what's behind the walls as well.

Since we moved here, my boyfriend's computer has rather abruptly started behaving erratically, and today something happened with my monitor that caused it to emit an incredibly high-pitched tone and not turn on. I had to unplug it for a bit to make it stop.

He was wondering whether the electricity is the cause. And if so, if there were some appliance that we could insert between the electronics and the outlet that would regulate current.

We're having a struggle getting the landlord just to address problems that no tenant can legally be expected to live with. He's not a slumlord, but it seems to take him forever to do anything, even when it's rather important. There is no hope whatsoever that he'd have an electrician look at the wiring in the house and pay for its repair unless we were completely without electricity.

Moving into another room with more outlets isn't an option because the computers and desks won't fit elsewhere in the house, and there aren't other rooms with 3-prong outlets besides the kitchen.

We're fools about eletricity, and my searching didn't turn up anything, likely because I don't know what to search for. We're worried that we may be slowly destroying our electronics.

posted by FortyT-wo to home & garden (16 comments total)

It certainly sounds like bad power could be your problem. What you want is a "power conditioner" and there are many vendors and styles of unit to choose from. There are small ones which you'd plug into the wall in that room and which would have outlets that you'd plug your computers and monitors into directly, and larger ones which would be installed by an electrician on the mains and protect the whole house against surges and brownouts.

Alternatively, you could get an "uninterruptible power supply" (or "UPS") which would protect even against complete blackouts by supplying power from a battery, but would cost more.
posted by nicwolff at 11:17 PM on July 7, 2005

Someone else can correct me, but most affordable UPS models just pass the AC through when it's fine, and switch to battery when the AC fails. So installing a UPS between the wall and the sensitive gear may not fix it. More expensive UPS's convert the wall AC to DC, switch that with the battery, and then invert it back to AC. Dunno if there are any affordable UPS's that do that, but that would almost certainly fix your problem.

Unless it's sagging voltage (i.e. less than 110 Volts), in which case you do need a wiring overhaul.
posted by intermod at 11:35 PM on July 7, 2005

Sounds to me like your wiring is old and tired, and that you do indeed have a voltage sag problem. You might be able to work around it.

First, make a little sketch map of your flat, and mark in the positions of your light switches and power outlets.

Next, find your fusebox. Make a sketch of that, too, and number the fuses on the sketch. If the fuses are numbered in the box, use the same numbers on the sketch to avoid confusion.

Pull out fuse #1. Now go round to every light switch and power outlet in your flat. For lightswitches, turn them on and see if the light comes on; for power outlets, plug in a desklamp and see if it works. On your flat map, mark every non-working light switch and power outlet #1.

Put fuse #1 back in, and pull fuse #2. Go round testing switches and outlets again as you did for #1.

Rinse and repeat, until you've identified the fuses that control every light switch and power outlet in the flat. You'll most likely find that the power outlet in your computer room is on the same fuse as some other outlets in other rooms, and that the lights run off separate fuses from the power outlets.

Now, unplug every appliance that's running off the same fuse as your computer stuff, and see if your unreliability problem has gone away. If it has, use extension cords to get those appliances and your computer gear onto different fuse circuits.

"...two computers with monitors, a TV, two lamps, some external HDs, musical equipment such as keyboard and mixers, and various things like cell-phone and battery chargers, etc. We've often marveled that we don't cause a brownout or blow a fuse in that room."

That's because you probably haven't actually added up how much power you're actually using with all that stuff. Computers will typically draw no more than about 300W (watts); monitors maybe 100W, TV maybe 200W. Keyboards and mixers will be somwhere around 50W each; cell phone and its battery charger probably under 20W. So although you've got a lot of stuff plugged in, even if it's all running flat-out you're probably drawing no more than 1200W off those outlets.

Outlets will usually be rated somwhere around 2400W total per wall plate, and fuses will generally blow if you put more than about 3500W of total loading on all the outlets they control.

By way of comparison: newer vacuum cleaners often pull 1300W all by themselves (most newer cleaners will proudly announce this somewhere on the casing); bar radiators, 1000W; fan heaters, 2400W; electric kettles, 2400W; blender, 600W; microwave oven, 1000W; washing machine, 600W; refrigerator, 1000W when running; hot water service, 4000W while heating; electric stove, up to 1000W per hotplate.

If you've got dodgy wiring, and you just happen to have a kitchen full of appliances running off the same fuse as your computers, you'll probably find that various things switching on and off in your kitchen will stuff up your computers, and that if you run the kitchen and the computers off different fuses things will improve.

If you get desperate, you could quite easily black yourself out just by running three fan heaters off the same fuse at the same time, systematically working around your power outlets until you've blown all your fuses. Then call your landlord and complain. Of course, there is some risk of finding out by this method that the old wiring in the walls is a weaker link than the fuses in the cabinet and making your flat burn down, so exercise your best judgement :)
posted by flabdablet at 6:03 AM on July 8, 2005

Uh-oh.

I hate to even mention it, but a few friends of mine moved into a house such as you've described, and it turned out that the previous tennant had replaced the fuses with higher-rated fuses than the wiring could handle ("they kept blowing, so I just got stronger ones"). This actually made it so that the actual wiring in the wall was acting as the "fuse" and was wearing out -- making the house a "brownout."

They needed to replace the wiring in the house. :(

But yes, normally, what you would need would be a good UPS, and one that says that it provides constant CONDITIONED POWER. Most UPSes will do this; I think actually that Best Buy sells a few UPSes. They also have a pretty decent guide to UPS protection.
posted by chota at 6:46 AM on July 8, 2005

You probably need legal advice, and that advice will probably go something like this:

1) Send a letter to the landlord and yourself which states the problem clearly.

2) After a reasonable period (two weeks maybe) send another letter that states your intention to proceed with repair, taking the cost off of your rent.

Alternatively, if you really really think you can't afford to rock the boat in this way, maybe you just have to foot the bill for a reduced price solution. I wonder if you could get an electrician to install one or two modern circuits. It might not be possible to mix systems in that way, but it would be relatively inexpensive and effective I think.

Before doing any of it I would follow fladablet's advice great advice about determining exactly what loads are on what circuits... Anybody having problems should do this. However, the "if you get desperate" part is a bit excessive (as I have confronted elsewhere it is quite negligent to use a safety device in a functional way).

intermod, that is the difference between a power conditioner and a UPS. Actually, I just checked a reference, because the terminology is abused a lot...

From a Power Electronics text a UPS should technically always be fully regenerating the output signal, so no need to switch over when there is a fault. A power conditioner has no switch mode power supply or battery at all, more or less a power bar. A supply that switches when there is a fault is a standby power supply.

The reason people get away with calling the thing you buy in staples a UPS is that a standby power supply contains a UPS that happens to not be used most of the time (which saves cost, is more efficient, is more reliable in some senses)... Maybe someone has a better set of definitions...
posted by Chuckles at 7:12 AM on July 8, 2005

I'm assuming from the fact that only some of the outlets are grounded (three-prong) that the flat in question is in the US. I'm in Australia, where we use twice as many volts and half as many amps to get our watts as USians do; we electrocute more people but our houses don't burn down as often :)

In Australia, lighting-circuit fuses are generally 8 amps, power-circuit fuses 15 amps. I expect US fuses would be rated about twice that; can somebody with local knowledge confirm?

In Australia, a house of your vintage would be fitted with ceramic fuse holders that take replaceable lengths of fuse wire, and there would be a little card lying about in or nearthe fuse box with some spare fuse wire wrapped round it - thin for lighting circuits, thick for power. With any luck, the card would have the fuse wire current ratings printed on it.

If your setup is like this: take the opportunity, after pulling a fuse, to check that there is ONE strand of fuse wire strung between the terminals at each end of the fuse. If some boxhead has doubled the fuse wire up to stop it blowing, fix it.

If it looks like you're supposed to have cartridge fuses but some dickhead with a deathwish has put nails or fencing wire or some damn thing in there instead, go and buy twice as many fuses as you need, and fit them!

After doing this, you may find yourself blowing fuses. That's a GOOD thing, because it means your wall wiring is no longer being asked to cope with more current than it's designed for. Unplug everything off the circuit whose fuse blows, fix the fuse, and reallocate your appliances to other circuits (extension cords and gaffa tape will help) until you can run all your stuff without blowing anything.

It may well be that this is simply not possible (there weren't as many juice-guzzling appliances made in the twenties) in which case you're looking at a rewire job.
posted by flabdablet at 7:52 AM on July 8, 2005

Oh yeah - precautions for "fools about electricity" who go poking around in fuse boxes: if you can see exposed metal contacts on your fuses, TURN OFF THE MAIN ISOLATOR SWITCH (it will be in the fuse box, it will be labelled, and it will make a very satisfying CLACK when switched) before pulling a fuse, and turn it back on before trying out your circuits. Even your feeble American 115 volt supply is enough to give you a nasty kick.

Separate from the fuses, you may see a totally exposed metal bar with a whole bunch of screws clamping a whole bunch of wire ends; don't be freaked out by that - it's the "neutral bar" that connects all the return sides of your circuits to ground potential, and should be safe to touch whether the isolator switch is on or off.
posted by flabdablet at 8:10 AM on July 8, 2005

After a reasonable period (two weeks maybe) send another letter that states your intention to proceed with repair, taking the cost off of your rent.

There are strict laws on when you are/are not allowed to do this in many jurisdictions. Screwing up could get you evicted and owing accelerated rent.

Do not not NOT do this without further research first on the laws of your jursidiction.
posted by grouse at 8:13 AM on July 8, 2005

A voltage sag could definitely cause the problem. I wound up diagnosing one such at my place of business due to the voltmeter built into the UPS that was supplying our server. (The server kept dying, the UPS battery was worn flat, and all because the new coffee maker in the kitchen was on the same circuit as the wall socket for the server. D'oh!)

I'd recommend getting a decent UPS with diagnostic bits built in; a lot of the newer ones these days have them and usually include software that will keep track of how much voltage the unit is receiving from the wall at any given time. Or, if you have one and know how to use it, a multimeter could do the same thing. (I like the UPS solution because it's standalone and will record its findings for you.)

Also: you may want to rethink the daisy-chain of power strips strategy. I've heard that cited as a fire risk (something about drawing too much current from one outlet or something, I think.).

flabdablet: the fuses in my house (US) are either 15 or 20 amps. I've heard of 10 amp house fuses, but never seen them. There are probably 30 amp circuits out there, but I don't think my house has any (built in the 40s).
posted by staresbynight at 9:19 AM on July 8, 2005

stares, if you chain a bunch of power strips together AND run radiators or fan heaters off them all AND the power strips have no overload cutouts AND a fuckwad's put nails in your fusebox, you have a fire hazard.

If you're running less than half the outlet's rated load into a bunch of juice-sipping technology, you don't. You're more likely to overload a typical dual wall outlet by plugging a heater into one side and an electric kettle into the other than by running a bunch of computers and stuff off a chain of powerboards.

It's all about total power consumption. The easiest way to figure worst-case total power consumption is just read the maximum number of watts each item draws off its nameplate, and add them up. If the result comes to less than the rated load for your wall outlet, you're fine.
posted by flabdablet at 10:06 AM on July 8, 2005

Oh, yeah: power consumption on nameplates is often given as a power in watts, while rated loads on wall outlets and limits for fuses are usually quoted as a current in amps. You convert amps to watts by multiplying the amps by your supply voltage (which for the US is nominally 115V).

For example: an 1150 watt bar radiator running off a 115 volt supply pulls 10 amps.
posted by flabdablet at 10:14 AM on July 8, 2005

Weren't houses in the 1920's wired with aluminum lines? That shit is major danger, especially if some fool has replaced fuses with higher-rated ones. I wouldn't be surprised if your household contents insurance doesn't apply in such a home; and I'm certain the landlord's insurance policy on the house itself is void.

The other dangerous wiring standard used separate wires mounted on ceramic posts. These, too, are dangerous: the original rubber coating will have disintegrated and started to fall off, exposing the bare wires.
posted by five fresh fish at 10:19 AM on July 8, 2005

Knob and Tube and Aluminum wire might not be up to modern standards, but they are not inherently dangerous.
posted by Chuckles at 11:47 AM on July 8, 2005

Wow, thanks all for your replies.

Some short answers... Yes, we're in the US. We don't have any fan heaters, electric radiators, etc. When the chandalier exploded, and my boyfriend was going to have to cut the wire that hadn't exploded, I ran to try to shut the power off in our flat. The downstairs neighbors told me it wasn't possible to shut the power off for our flat only. A look at my fuse box made me think she's probably right.

I could easily map out which fuse goes with which outlet in our flat and I will definitely do that, but the trouble is the basement is a tangle of wires, with little outlet boxes hanging from the ceiling, random fluorescent lights without chains to turn them on, etc. We also have light switches in the apartment that aren't connected to any lights or outlets. I guess they were disabled at some point. I know some of the basment outlets are ours (our neighbors have their dryers plugged into one of ours since none of theirs will power a dryer). Just not sure if I could find them all.

Here is a picture of our fuse box. (Large version so all the voltages can be read.) To me, it looks relatively new and untampered with. For comparison, this is the scene just outside the fuse box. Most of the basment looks similar to this, with wires running all over the place.

Especially with talk of insurance being voided (eeeek) I'm thinking this is a job for an electrician.

We'll pick up an UPS system and ask the landlord about having an electrician out. Unfortunately I think this is a case where we're in over our heads.
posted by FortyT-wo at 11:56 AM on July 8, 2005

That's an older style fuse box. The modern way is to use breakers, not fuses.

You probably can turn off your power by pulling the handle out and inserting it back in upside down. When the handle is out the mains will be exposed so be careful. You should also doublecheck any outlet/circuit you are going to work on with a voltmeter first.

How attached are you to this place? If the landlord isn't willing to address the electrical issues, you ought to consider moving. Find resources where you live but I would think (currently*) unsafe wiring might be a valid reason to break your lease.

* My guess is fuses too large for the wiring but it's not your responsibility to fix.

RE: aluminum wiring probably isn't in a 20s house.
posted by 6550 at 12:57 PM on July 8, 2005

Call a qualified electrician to inspect if your landlord won't. Don't mess with this yourself. I'm serious. You don't know enough, and a mistake could be fatal or very inconvenient and expensive. Once you have the inspection in hand, if it shows subcode wiring, you will have a very powerful instrument to compel your landlord to act.

Who knew there were so many electricians here!
posted by realcountrymusic at 2:40 PM on July 8, 2005