Low/high-voltage household wiring system

Old 10-13-02, 01:39 PM
1949 Nightmare
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Low/high-voltage household wiring system

Need suggestions/helpful comments/info on repairs & specs -- lw/hi-vltg home wiring syst. circa 1949. House has intermittent low-v pwr probs. Unfamiliar with current codes and trblshooting this type of system.
Old 10-13-02, 02:26 PM
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A answer to that could turn into a book. So to keep this from happening, can you go into a little more detail to the problem your having with it? thanks
Old 10-13-02, 09:20 PM
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time to rewire!

Try Shapiro's book "Old Electrical Wiring" (McGraw-Hill). His more recent "Your Old Wiring" is a "lite" version, and might be a good introduction.

I think the best long term solution is to rewire the whole house.

It's going to be very difficult or impossible to find an electrician to troubleshoot the low-voltage system. Unless you find an old-times who has experience installing them...you might look in retirement homes or ask at the electrician's local. Even then, it'll probably be impossible to get new replacement parts. You could possible scavenge parts from houses in your area being demolished, if the low-v systems were common in your area. In my area, (Sactramento, California), they were used only in the more expensive homes. Every home I've seen that used to have such a system has had it removed for the reasons above--no parts and no one with experience to do the work.

And as far as doing it yourself, well, troubleshooting takes a good basic understanding of electricity (circuits and safety), a good multi-meter, a circuit tracer, and experience. If you want to make this your hobby and chip away at it over a period of months, give it a try. IF you just want to fix it ASAP, it'll be nothing but frustration.

Don't mean to discourage you--just being realistic.

Old 10-14-02, 08:28 AM
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Maybe this will help some.

Low voltage switching is not that complicated!

The actual switching of the line voltage takes place through something called a solenoid. This unit is like a remote control switch, one side of it is low voltage and the switches in the rooms are tied to the low voltage side of the solenoid.

Commonly, the low voltage switches are the rocker type of switch. Push the bottom of the switch and the light goes off, push the top of the switch and the light goes on. This requires three low voltage wires to each switch. One wire is a common and the other two are the off and the on signal wires. The common carries the low voltage to the switch in the rooms and the signal wires operate the solenoid.

The other side of the solenoid is the line voltage switching side. The hot conductor is tied to one side of the line voltage side and the switch leg, that operates the light itself, is tied to the other side of the line voltage side of the solenoid.

The most common problem with low voltage switching is the solenoid going bad, when this happens it can fail in either position, off or on depending on whether or not the light was on when the solenoid failed. If the installer left you any kind of a legend it will be much easier to determine which solenoid operates which light. That is probably the hardest part of working on these systems.

To troubleshoot you will need a meter that can read the voltage the system operates at, most of them are 24 volts and you will need to be able to measure the line voltage as well.

You start by finding the solenoid panel or panels. Everything comes into these panels so you will encounter lots of different wires. If none of the low voltage system works then check the transformer first, to make sure that your transformer is working. Once you have verified that you have the control voltage then you have to locate the solenoid for the rooms that are affected.

This will be a lot easier if you have someone to help you! Once you have found the solenoid you need to identify which wire is the common on the solenoid and which wire is the "on" and which one is the "off". When you have done that, attach one probe from your meter to the common and then attach the other probe to the wire that you have identified as the "on". Have your helper push on the switch to turn the light on and see if you get a voltage reading. If you do and the light doesn't come on and you don't hear the solenoid "click" you have found a bad solenoid.

It may take a little bit of doing to find the parts but, they are still available. You may have to get them through some kind of parts reclaimer, these guys go in and gut old buildings and houses and salvage any of the parts they can, shelve them and then sell them to people who have need for them.

This won't be an easy task in the beginning however, if you spend a little time and learn your particular system things will get much easier. Patience is a huge virtue when troubleshooting low voltage lighting circuits. I am sure that your sweat and the cost of the replacement parts will be much lower than a total rewire of the entire house.

Hope this info helps and if you need more help, don't hesitate to post here again.

Good Luck!!!!

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