Buying old house, need advice.

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  #1  
Old 11-08-04, 01:28 PM
Jasper1
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Buying old house, need advice.

Hey everyone. I am buying a house built in 1911. The electical and circuit box is all new with 220 power. The problem is I don't think new electical has been run to each outlet.

I have a lot of electronics and computers and want to make sure all my wiring is safe and can safely handle the power. I want to have an electircian come over and upgrade the outlets. What kinds of things should I look and ask for?

Also, since it is an older home. Is there any type of battery backup you can put at the source inside the house to protect power if power goes out for a few minutes and to protect flashes.

Thanks in advance.
 
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  #2  
Old 11-08-04, 05:23 PM
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Since this will be a rewire job be sure to ask about damage to walls and who will repair it.
 
  #3  
Old 11-08-04, 05:30 PM
Jasper1
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Do you think the old outlets need to be rewired? I mean the previous owners ran normal stuff on the outlets without problems. Does the WHOLE wiring need to be updated or can something just be changed at the outlet?
 
  #4  
Old 11-08-04, 06:05 PM
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If you can put all your electronics and computers in one area of the house, you can have one or two grounded circuits installed to that location. This should help to keep the costs down. To control power surges, you can have a TVSS (whole-house surge suppressor) installed at your panel, and also use surge suppressor power strips, and/or you can use a UPS.
 
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Old 11-09-04, 10:16 AM
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Jasper1,

John Nelson suggested a UPS, and I felt that not everybody knows what that is. It stands for Uninterruptable Power Supply. It contains batteries, a charger, and an inverter, which is a device that converts DC (batteries) to AC (household current). When the power goes out it switches to battery backup in microseconds, less time than it takes your computer to realize there was a blip. It also has "power conditioning" usually, which prevents voltage spikes, voltage dips, and "noise" on the line that could affect your electronics. These are available at computer stores usually. They are about 6" x 6" x 12", they weigh about 10 pounds or so and are self-contained. They come with a power cord and usually two built-in receptacles to plug your equipment into. Those two receptacles are protected from outages, dips and spikes.

But be wary of the TVSS, or "transient voltage surge suppressor", power strips. Most of them are not TVSS, but simply have a mini circuit breaker (the little red "reset" button.) The mini circuit breaker merely protects the electrical cord on the power strip so you don't overload it by plugging too much stuff into it. It does little or nothing to protect the equipment you plug into it. There is no "reset" button on a true TVSS power strip. If you get hit by a spike, there's a gizmo the surge goes through called an MOV (metal oxide varistor), which basically burns to a crisp and you have to toss the unit. But it opens the circuit to your equipment, and that's what you want during a surge event, such as a lightning strike. These power strips aren't nearly as cheap as the cheap-o kind you'll find at Office Max, but they are much cheaper than your computer.

One thing that comes to mind in older houses where previous owners did upgrades. Many replaced 2-prong receptacles with 3-prong types, but the original wiring is still in place, which had no ground wire. This is only code compliant if the receptacle is GFCI protected and has a little label on each such receptacle that says "no equipment ground". Since receptacles are normally wired in series, you can put a GFCI receptacle at the beginning of the string of them (electrically - the closest one to the electrical panel), then connect the rest of the string to the "load" side of the GFCI. All receptacles on that string are now GFCI protected and may be 3-prong types if you label them. Some GFCIs come with a sheet of tiny labels for this purpose. If there is a ground fault in any of the receptacles downstream of the GFCI at the beginning of the string, including the GFCI receptacle itself, the GFCI will trip and you will be safe.

So, pull out a receptacle in an area where you would like to plug in electronics and see if there's a ground wire. If there is, you're set in that area. If there isn't, you may want to consider the above. Or you certainly may have new wiring installed from the electrical panel throughout all the receptacles in the area where you want to safely use high-end electronic gear.

Hope that helps.

Juice
 
  #6  
Old 11-09-04, 10:24 AM
Jasper1
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Thanks for all the help guys. Few questions based on your feedback.

I know the "entertainment" room where we will be moving our high end TV and such only has the two prong outlets. So simply switching over the covers to a three prong one won't exactly ground it. What would it entail to do a proper grounding?

Also for the UPS - I have one now with four outlets. But is it ok to plug a surge protector into one of the outlets for more outlets?

Finally, is their a UPS you can put at the main breaker of the house? So if the whole house were to lower power, the battery would kick in. I'm not talking about powering the house for hours or days, but just to cover the occassional power flash or few minute outtages.

Thanks again!
 
  #7  
Old 11-09-04, 10:58 AM
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Jasper1,

The only way to properly ground a circuit of receptacles is to replace the wire from your electrical panel to all the receptacles you want grounded. Which leads back to the suggested question of who's going to fix the walls.

This is a true case of if you want to make an omelet you have to break a few eggs. No way to re-wire usually without busting holes in the walls to run it. An experienced residential electrician would be minimally invasive, and I'd expect you could get a new circuit in one room for a couple hundred bucks. You'll probably have to get get the holes fixed yourself, I don't know any electricians that will do plaster or drywall repair.

One thing to note - I believe a true TVSS, and also UPSs, require a grounded circuit in order to work properly.

A whole house UPS would be expensive. These units are pretty expensive, but installing it would be really expensive. And people with that kind of money will usually go ahead and get a generator and automatic transfer switch installed instead. But generators ordinarily take 10 seconds to get up to speed and switch over. Your computers will be long gone by then and you'll lose any unsaved data. I used to work for a battery company, and did a lot of corporate and government computer centers. These guys ain't fooling around - they have a UPS, multiple strings of batteries AND a generator. They ain't going down!

I'd say the desktop UPS units are the most practical for the average homeowner.

As for using a multiple power strip to plug more stuff into a single receptacle, that's what they make them for. But I have seen people plug a power strip into a power strip and have 10 things running off it. Most older wiring is 15 amp rated. If you don't think you're pulling more than 15 amps on the entire circuit, you should be OK. TVs, computers and stereo equipment are not notoriously high-draw equipment. They're usually in the range of a couple hundred watts +/-. If you figure 120 watts = 1 amp, you can probably reassure yourself of how much stuff you can safely plug into a given circuit. There should be a nameplate on most of your equipment that tells you how much power it uses. Otherwise, you can usually find the power requirements in the owner's manual. Sometimes it shows the power in watts or sometimes in VA (volt-amps). Loosely speaking, you can generally estimate that one watt = one volt-amp for the purposes of this exercize.

For a 15 amp circuit, and with older wiring I would assume that rating, a fair recommendation would be to keep your load down to 1,530 watts, which is 12.75 amps, which is 85% of the circuit's 15 amp rating. (Load calculations in the NEC specify that you design a circuit to not exceed 85% of the circuit's rating.)

If you're going to have a receptacle circuit replaced, I would recommend having it upgraded to a 20 amp circuit. There is only the tiniest difference in cost. The electician would install a 20 amp breaker (same price as a 15 amp breaker) and run all #12 wire, which is rated for 20 amps. You can put 17 amps, or 2040 watts on a circuit like that.

Hope that helps.

Juice
 

Last edited by JuiceHead; 11-09-04 at 11:09 AM.
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