Low Voltage Wiring questions & answers:

Diagnostic questions help repair low voltage wiring systems in buildings.

This article series provides a diagnosis and repair guide for low voltage electrical wiring typically used to control 120V home lighting, electrical receptacles, and other devices.

We discuss low voltage electrical wiring inspection, diagnosis, repair, parts replacement, finding low voltage relays, replacing low voltage relays, finding low voltage wiring diagrams, and low voltage electrical wiring parts from GE®, Remcon, Sweepe, Bryant, Sierra, Touch-Plate®, general use low voltage relays, and where to find home electrical system low voltage wiring diagrams helpful for performing low voltage wiring repairs.

The photo at left shows a GE low-voltage relay box in a residential attic. Photo courtesy of True Tech Electric.

Low voltage electrical wiring (GE, Remcon, or Other Low-Voltage Building Electrical Wiring & Switches) was installed in some homes beginning in about 1946's. This system was popular and was installed in many homes between 1960 a nd 1985, and it continues in use today.

On 2019-06-08 by (mod) - bad low voltage wiring rocker switch for light

I'd like to help but I'm confused by the question. Perhaps you could make a drawing or show me a photo of the wiring.

It sounds as if there's a bad rocker switch - yes most low-voltage light switches are on-off. Remember to also check the relay.

On 2019-06-07 by Chuck

On a Bryant lv rocker switch I' m getting 24 v on the black and red wire checking it to the common on the switch whether I toggle it to the on or off position. Shouldn't one side go to 0 volts when I toggle? also the relay to turn light on does not engage to close contact on relay. Can you help me out on this one?

On 2018-09-12 by (mod) -

Scott:

Yes there were several brands of light switches, including from Remcon, that absorb energy and glow in darkness or dim light. Kyle Swtichplates is among suppliers selling replacement parts for low-voltage lighting systems including replacement parts for old Remcon switches.

Here is what Kyle says:

Old style ovoid Remcon switchplates were typically installed horizontally with switches rocking up and down vertically to turn lights on and off. The wall plates were clear plastic with a gold backing paper. The slightly flared switches were pinched in and narrower at the middle, then wider at the top with a small centered dot.

These hourglass-shaped switches were a bone color and were impregnated with a non-harmful phosphorescent material so that they glowed in the dark for about an hour after the lights were turned off before eventually fading.

Note that the original type of Remcon mounting straps, ivory curvy rocker switches and rounded or oval wall plates are no longer in production and were eventually replaced with newer line of black Remcon snap-in switches and stainless steel cover plates (discontinued in 2011). - source: Kyle Switch Plates, retrieved 2018/09/12, original

source https://www.kyleswitchplates.com/remcon-low-voltage-lighting/

On 2018-09-12 15:43:55.483907 by DJ

I have low voltage system and there are 2 electrical outlets that are both tied to the same 2 3-way switches. I want both of these electrical outlets to always stay on and essentially bypass these 2 3- way low voltage switches. Is there an easy way to do this and then I can literally remove those switches? I have disconnected one of the switches but then the outlets immediately stopped working.

Any help is appreciated. I don’t know low voltage but I am a saavy DIYer and can troubleshoot normal electrical issues. Thanks in advance.

On 2018-03-29 19:47:06.679363 by Scott

My son recently bought a house built in 1957 that has the Remcon low-voltage switch system, and we were noticing the other day that the rocker switches actually will glow in the dark after being exposed to light for a while, but I believe the glow effect tends to fade rather quickly. Is this how the switches were originally made?

On 2017-01-11 by (mod) -

Brian:

One way to determine if the problem is a low voltage toggle-type "on-off" switch is to jump the two switch wires together - that's the same as turning the switch "on" - if the switched circuit or light stays off the problem is probably the relay control or a wiring defect, assuming you know the bulb and fixture are good.

I'm not sure just what type of switches you have installed. If you have a type of "rocker switch" that does not flip to a solidly on-or off position, that is, if it's a type of "press to operate" switch, then I wouldn't jump its wires together as that might burn up a relay or low voltage transformer.

If you can identify the type of switch, brand, model, labeling, or send along photos (page top or bottom CONTACT link) that might let us comment further.

On 2017-01-11 by Brian

I have low voltage system in my house. Some area of the house have one rocker switch, other plates have 2, 4,even 6. My bedroom has 9 switches. I ordered a 2 switch plate for every single rocker. I believe I need to order a 4 for every plate with two switches? Am I right about this? I just confused how to wire these.

Also, I am not sure if a switch is broke because some lights dont even work even when I install a new bulb and twist it on. Could this be a relay? I can't even find these relays in my house.

On 2016-11-03 by John

Do all of the GE LV lighting systems use a "transverter" that also converts to DC? I bought a house with GE LV lighting and it has a transformer that only reduces to 24VAC. It has been working for 18mths and then ceased to function yesterday.

I am in a house upgraded in the 70s with a 12v lighting switch system that has 120v light fixtures and wiring. I was able to replace all of the system with 120v switches however due to wiring issues to the remaining switch I need to keep that one 12v. What transformer and switch and wire gauge would I purchase? Is there a low voltage switch and transformer other than the 12v that would be more recent tech?

On 2016-09-12 by Richard

Can I totally take the low voltage box out and run the wiring to a 120 volt switch and have my lights work

On 2016-06-04 by (mod) -

A short circuit somewhere in the system

On 2016-06-04 by Anonymous

I have replaced my transverter box because all of my lights that were on, stayed on and the ones that were off stayed off. The tranverter box would burn you to touch it. everthing is still the same. What could be my problem?

On 2016-03-17 by (mod) -

If the same transverter is powering all 6 lights then more likely the problem is failing bulbs or bad wiring.

On 2016-03-09 by Rod Johnson. rjohnson@gprnm.com

I have 6 lights on a low voltage circuit. Occasionally only 2 will turn on. Is this a transverter problem or something else?

On 2015-07-20 13:48:03.726506 by Bill

I have a Sierra lighting controls in a house that is being remodeled. All the wiring for the relays , switch legs and the transformers has been disconnected. Where can I get a wiring diagram in order to reconnect them ? There is five relays , five switch legs for the exterior flood lights and two transformers. There are also five three conductor low voltage wiires hanging next to the junction boxes.

On 2018-08-20 - by (mod) -

fix the low voltage lights in a bathroom

Coy

In essence, follow the wires.

If the problem is a switch then jumping the switch wires will turn the lights on.

If the problem is a relay, swapping one from lights that work can confirm that was the issue.

Watch out: if you're not familiar and trained in electrical work you could be shocked or killed, especially at the line voltage connections and wires.

On 2018-08-20 byCoy R Nichols

How do I trouble shoot low voltage to the lights in bathroom , bed room and bathroom. They don’t work

On 2018-05-19 by (mod) - a noise problem in the consumer unit

forgive me, but I don't know what you mean by

Consumer unit

On 2018-05-18 by henry Thake

I have a noise problem in the consumer unit ( fuses for the flat circuits) is recurring at various time intervals!
Even if I switch off the main switch it still happens!
Have you any explanation?
Thank you
Henry

On 2018-02-09 by (mod) - when some lights work and some don't

Richie

If some of the lights work and others not on a circuit I would be looking for

- a bad wire connection

- a bad bulb

- a bad local transformer

- a bad switch

On 2018-02-08 by Richie

I have installing a all new landscaping lighting.
it is a 300W transformer with 2 ways.

my 1st run wire is connect with 6 supply lights: (2 of them don't work) I tried to switch them but these spots never work

my 2nd run wire is connect with 4 supply lights: (2 of them don't work neither) I tried to switch them but these spots never work

do you have any idea ?
thanks

On 2017-12-04 by (mod) -

I'm not sure that I understand the question correctly, but it sounds to me as if the low voltage relay switch has failed.

On 2017-12-04 by Anonymous

we have a low voltage system and one of the lights stay on and the wire hooked to the output of the relay is live with 120 volts the relay switches the 120 volts when the wire is disconnected. why could the wire be hot

On 2017-11-16 by Bob

I have always had a motion activated security light on my Remco low voltage system. Never a problem. I never turn the switch off. The switch is always on and the light worked properly dusk to dawn.

Recently the power company pulled my meter and put in a 'smart meter' and immediately the light randomly started coming on, then off, on, off..all night long. Replaced the fixture and problem continues.

Could the meter swap have damaged the transformer relay? Should I even be able to use this type of light with the relay? Any ideas?

On 2017-08-23 by (mod) - variation in supply voltage level

Abdul

Start with your power company: depending on where you live voltages can vary considerably.

Next high loads on a circuit such as equipment switching on can dim lights.

Dangerous: dimming can also be caused by electrical short circuits for example to earth - that justifies investigating the wiring system to be sure there are no dangerous situations as someone could be killed. I've seen this when someone put up a metal fencepost that cut into the buried electrical cable.


Joe:
Check the voltage at the switch control boxes or at at least one you can access.

On 2017-08-23 16:45:00.774446 by Abdulraheem Taofeek

What Exactly Is That Can Cause A Low Voltage In Building When The Light Is Switche On

On 2015-10-29 09:06:56.489252 by joe

all switches stopped working. none of them are stuck...the usual problem. do i need a new transverter?
thanks!!

On 2015-09-16 21:53:24.297784 by Catherine

Can an old low voltage residential system cause problems for land line phone service?

On 2014-08-14 21:38:00.788330 by Arrhur Belefant

Is there a qualified electrical contractor for a GE low voltage lighting system in or near Brevard County, FL?

On 2014-07-13 20:28:36.019360 by (mod) -

Deb,

Grasslin Controls is a UK company, part of the TFC Group, who can be contacted directly so that we get this right. See

http://www.grasslin-controls.co.uk/
TFC Group LLP
Tower House
Vale Rise
Tonbridge
Kent
TN9 1TB

Tel: 01732 351 680
Fax: 01732 354 445

Since I didn't see your LV power control listed, I'd give them a call or an email.

Daniel

On 2014-07-13 19:32:10.342590 by deb

does the grasslin 30600-172 low voltage power control have a reset button? There are 2 switches on the control panel but I dont know what their function is. My landscape lights do not come on at all, but there is power to the power outlet, the timer appears to work, & I have checked the bulbs.

On 2014-05-08 14:42:49.179930 by (mod) -

Thanks anon.

On 2014-05-07 19:58:44.347570 by Anonymous

Michael, look in the light box right next to the light. some relays are in there

On 2014-04-03 18:57:30.077890 by (mod) -

I was sure we'd talked about this - perhaps the comments got lost. Typically the relays are in a box in a ceiling, crawl area, adjacent garage, etc. not necessarily right at the panel.

On 2014-04-02 17:44:43.280100 by Michael

Having issues locating the relays in a church, one of the switches is near a breaker panel but (assuming) the relays would be in it's own panel what other areas should I look for them at? I've checked about every closet, I have a bank of lights that wont turn on and it's the GE control switches with the On and Off dials.

On 2014-03-15 22:20:24.424230 by (mod) -

Jeff, you can use the CONTACT US link to send me some photos and I'll both comment and if you wish, post them here to invite assistance from others.

Often even though you cannot find an exact relay replacement you can find an equivalent that works.

On 2014-03-14 20:56:10.375030 by Jeff Johnson

I recently took over as Grounds Keeper for a local church. They have the LV GE system in the main sanctuary. We have had trouble lately with one of the overhead lights. I have found the relay box tucked away in a furnace room. The switch controls 8 different lighting locations and they all work perfect except for one.

After reading this article and all the post I am assuming its a bad relay. I have not heard mention or even seen a switch like they have though. Its a round dial numbered 1-9 with a on/off toggle pad at the bottom. On the back is a round (potentiometer) looking housing with 10 red 10 black wires and terminals. Wish we could show pictures here. Thanks for the article and the help. I will get back to troubleshooting the relay Monday. Will let everyone know here so maybe to help someone else.

On 2014-03-11 20:13:21.523480 by (mod) -

Anon

Good question.
Because they need to be accessible for service the low voltage relays are not usually buried in walls or ceilings (which would also violate the NEC).

Look in:

- the attic floor
- the basement ceiling
- unfinished walls of a garage or utility room

Let me know if you find them somewhere else as that may assist other readers.

On 2014-03-11 19:55:50.497540 by Anonymous

where would you usually find the low voltage relays at, i have a old remcon system

On 2013-04-01 17:30:26.520473 by (mod) -

Charles,

No that does not sound normal. Sounds like a short or miswiring. Leave the system OFF and call your heating service tech. Usually the residential heater gas valves operate at low voltage - 12-24 VAC or even at millivolt levels depending on the model.

On 2013-03-30 20:56:15.431823 by charles

i have a honeywell aquastat type l8148a an it fryed my gas valve. i tested the voltgae to the gas valve an it is puting out 121.3 v ac is this normal

On 2013-02-26 16:18:32.862436 by Anonymous

causes of drop of nominal low voltages from 220v ac to 110v, 150volt and 80 vac on third phases in electrical wiring fixtures, fittings and home appliances. Answer pl

On 2013-02-22 16:51:41.248930 by Mel Schwarz /jarvis

Trying to identify a master electronic controller in a low voltage lighting system

On 2013-02-13 17:43:25.652340 by Tony

I was asked to assist a general contractor friend who had never encountered a low voltage home system. I did commercial general maitenance for 10 years and hvac the last 20 years, so my friend asks for my help every once in awhile. So I went into the attic to determine which relays were for what, and found they were labeled.

Now the problem, one of the bathrooms light would not turn off, so my friend took off the wall switch and tested it bad. So he replaced the switch and then the relay would not engage, so I replaced the relay and the first few times the light turned off and on and then the same problem, the light won`t turn off again. So I can hear the relay clicking in and out but the light stays on? Any suggestions??

On 2013-01-17 20:20:38.753612 by Stan

I am purchasing a home with a low voltage electrical system, and need to cover the open electrical wiring before closing. I was wondering if anyone had any suggestions. I was going to use wire sleeves but worried it won't pass.

On 2012-11-23 06:14:49.879774 by (mod) -

Doug, I read your comment and speculation but didn't see a specific problem nor question.

The original concept was to save on more costly heavier copper wire by using it only where necessary to conduct current to the end using device. That approach can also be safer in some respects. The system was nor a gimmick in my view, but I agree that compared with systems that don't have to include a bunch of relays, LV is more complex and at old age more trouble. So the money saved on copper at installation may have been repaid in parts and labor by now.

On 2012-11-18 by doug

cliff and i seem to have the save problem...cliff did u find a answer to your problem....

On 2012-11-08 by Doug

I find this low voltage electrical system very interesting.

I discovered it on an internet search and it peaked my curiosity to learn how it worked and why this system is/was chosen over conventional 120v wiring

. I live in the Chicago metro area and I've been in thousands and thousands of homes, most of which were built in the 1950's-early 70's (the peak years these low voltage systems were installed) and have never once seen a low voltage system in or around the city or suburbs

. That leads me to ask a question; were low voltage systems more commonly found in different parts of the country and how common is it?

As an outsider, it seems rather gimicky to run transverters and relays to function lights only for the sake of cutting back on installation costs or saving money by running lighter gauge wire to switches. In the long run, it doesn't seem very practical as there are numerous components which are subject to failure and/or require "maintenance" to keep things working right.

I personally wouldn't have a problem with it as I like relays and electro-mechanical devices and the like and having to service one of these systems would be rather fun for me

I'm just trying to look at it from the average homeowners point of view who probably isn't thrilled about having to replace transformers and relays just to make their kitchen lights turn on... I appreciate anyone's comments/input. Thanks!

On 2012-09-15 by Jon

Does anyone have experience of operating ham radio in a home with these low voltage relay lighting systems? I.e, can high power RF trigger the relays?

On 2012-08-23 by Jeff

If all the others work, then the transverter is sending the proper voltage to every switch and it is more than likely a relay problem.

On 2012-08-22 by Mike

I have one light that works on occasion. I have changed the switch out and haven't had any luck. I will come on if you repeated push the on switch. I can hear the buzzing sound when I push it off. Could the relay be problem? All of the other switches work properly so I am at a loss.

On 2012-08-2 by Jeff

MARK
if I were you, I would buy a volt meter that reads DC voltage as well as AC. Make sure your new trabsverter is outputting 28-30 volts DC. It IS possible to have bad new parts.

On 2012-08-16 by mark

I went ahead and replaced transverter, and now non of the lights work, I was able to get one light to come on,but would not turn off, Help!! thanks

On 2012-08-16 by mark

have issue with touchplate system. 3 of the touch plates in house intermittently turn lights on. hit the button you hear the relay and light flickers but will not stay on. Other lights in house work fine. I thought issue was with touch plate switches,so I pulled of touchplate and touch bare wired together, and same thing happens,hear click and no light. DO you think its possible the transverter/power supply is going out. I went up in attic and disconnected the wire that went to the switches, and nothing in house will work,so I assume that is the only power supply for house. I have also read that maybe a relay is going out,but then I thought how could 3 go out at same time. thanks for advice. mark

On 2012-07-26 by (mod) -

Annie, you will Want to find all of the low voltage control boxes. At each (there may be more than one) confirm that 120V is being delivered to the box - starting at the electrical panel if necessary.

If none of the low voltage devices are working I suspect no power to the LV control box or a vad low voltage transformer.

If some LV devices work and others not, more often that trouble is traced to a switch or relay.

On 2012-07-25 by annie

our house is about 30 years old and we have low voltage.. weve been having few problems lately.. we have no more contact between the switch and the panel.. everything was change but we can t close or open any lights in the house at all.. all we can do is close the breaker and same thing if we want lights...
all high voltage works fine ? we call a few electrician but they seems lost with that system..

On 2012-06-01 by (mod) -

Good progress, Cliff. I think the low voltage relay panel was often located in an attic or garage as a compromise among these rules:

- codes prohibit burying electrical boxes and panels hidden behind walls or ceililngs - they have to be accessible

- on one wanted to look at that rats nest of complexity as it was often sloppily installed, sometimes by an amateur

- while it would be more convenient to locate the collection of low voltage relays in a garage or baswsement -more accessible, that is, the wire lengths would be increased

Check with the suppliers we listed above when you determine that you need to replace an RR5 relay.

On 2012-06-01 by Cliff

Thanks, gentlemen. Here's the latest. I crawled back up in the attice and disconnected each relay one by one while my wife turned the wall switch on and off. Crude and not at all effective. No luck. Them light mad fan come on early in the morning and late at night, but not during the heat of the day.

The problem seems to be heat related. I understand these relays are heat and cold sensitive, so that is likely the problem.

Why the box was mounted in the unfinished attic is beyond me. A real pain. I located a local electrician who is coming next week to look at it. I suspect at least one relay will need to be replaced. I don't know the yep off hand, but suspect they are the RR5 type. Is there a suitable replacement for the RR5? Again, many thanks.

On 2012-05-29 by (mod) -

Stan / Anon:

It sounds like a bad relay - a part that does indeed fail. It's also common that you find a rats nest of messy, un-labeled wiring.

You may be able to find the right relay and wires using a wire tracer device sold for circuit identification, or by using a VOM. When you think you have the right relay, and on the theory that you're lucky enough that just that one is bad, try temporarily swapping in one of the other relays to see if that fixes the trouble.

On 2012-05-27 by Anonymous

Thanks for the response to my question. There is current coming into the wall switch, which I replaced. The fan and light now work intermittently. I crawled into the attic and looked at the relay box and transformer. Could see nothing amiss. My best guess now is it's a bad relay, working at times, not working at others. The relays are not marked as to which serves what switch. Is there a way to locate the problem relay? Thanks, again!

On 2012-05-22 by (mod) -

Stan, just a few guesses:

- a failed relay

- a bad light switch

- loose wires anywhere in the low voltage system

- a bulb with a failing filament, with the circuit in the "ON" position may flicker between on and off

Cliff:

I'd check in the main box you described, for a loose wire or a bad relay. Also check the rocker switch itself with a VOM to see that it is working

On 2012-05-22 by Stan Sarnacki

What might cause low voltage controled lighting in a home to come on without the switch being activated?

On 2012-05-19 by Cliff

We have a home built in 1964 with the GE low voltage system. The fixture in our den has a ceiling fan with light kit. A couple of days ago, I touched the rocker switch and found neither the fan nor the light would come on. We replaced the light kit and checked all visible wiring coming from the ceiling and into the light kit. No problems were seen.

I tried two more switches with no success. It appears there is no voltage getting to the switch. The main box for the system is in the attic, but it seems like if the problem was there, more than one switch would be affected. Everything else on the same circuit works fine. Any suggestion and ideas as to what the problem is and how it cab be fixed would be greatly appreciated. Thanks!

On 2012-02-14 by Joe

Does anyone have a wilring diagram for this low voltage lighting system. 2 of my lights are fluorescents and the relays were right inside the ceiling next to the 14-2 wire coming out for the ligh (i dont remember how it was tied together.

I need to know how to rewire the relay to the new modern light while tieing it in to the 14-2 wire so i can turn it on and off

On 2011-12-10 by Anonymous

I want to run a gas fireplace off a 24vac thermostat and also connect it to a 120vac blower fan

On 2011-12-10 by Paul

There's no need to replace a 3-wire system with a 2-wire. GE still makes switches and RR-7 & RR-9 3-wire relays for their "Total Lighting Control" system for commercial and industrial applications. Pass & Seymour make 3-wire switches and relays that are identical to the old Sierra ones. Do a web search or check with a good electrical supply. They are available, though not cheap. I'm installing new lighting circuits in my own house that use these because it simplifies multi-point switching.

On 2011-11-27 by (mod) -

Steve, you pose a good question about 3-way light switching on low voltage lighting, but it's beyond my expertise. If you contact one of the low voltage wiring product suppliers we list in this article I'll bet their technical service rep will be able to answer the question immediately. Keep us posted, what you learn will help other readers. DF

On 2011-11-23 by Steve

I have this system in my 1955 home and think it is great. I can turn lights on and off from multiple locations and have 2 dials at different locations a can turn on/off lights throughout the house. I have a light that has the relay connected directly to the fixture but it is a 2 wire relay with the wires connected together for this. Any suggestions on how to reconnect wires to allow the 3 wire relay?

On 2011-07-30 by Jim

Father-in-law built house in 50's w this type of system some relays are now bad info here sounds good & a place to possibly find parts thanks

...

Continue reading  at LOW VOLTAGE WIRING REPAIR or UPGRADE or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Low Voltage Wiring Articles

• BOILER CONTROLS & SWITCHES
• FURNACE CONTROLS & SWITCHES
• HEAT WON'T TURN OFF
• HEAT WON'T TURN ON
• LOW VOLTAGE BUILDING WIRING
  • COMMON WIRE at THERMOSTATS
  • LOW VOLTAGE WIRING SYSTEM COMPONENTS
  • LOW VOLTAGE LIGHTING & CONTROL RELAYS
  • LOW VOLTAGE TRANSFORMERS, TRANSVERTERS, CONVERTERS
  • LOW VOLTAGE TRANSFORMER, TRANSVERTER DIAGNOSIS
  • LOW VOLTAGE TRANSFORMER TEST
  • LOW VOLTAGE WIRING REPAIR or UPGRADE
  • LOW VOLTAGE WIRING REPAIR PARTS SOURCES
  • THERMOSTAT WIRE CONNECTIONS
  • THERMOSTAT WON'T TURN OFF
  • THERMOSTAT WON'T TURN ON
• VOLTS MEASUREMENT METHODS
• ZONE DAMPERS
• ZONE VALVES, HEATING

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