What is its intended purpose?

[JesseWBryant]

Anyone know what this device is used for. I found it two of them today in a model home that was being sold. There were two of these in a metal box with multiple branch circuits coming in the bottom and one romex cable coming in the top.

The builder had a single switch installed near the front door that controlled the power to outlets and light fixtures in all the bedrooms, living room, dining, etc.

The buzzing sound that eminated from this box was tremendous and the volt drop readings that I picked up from some of the outlets were as high as 20.8 (on a 20amp load).

The buyer said that the builder was going to do away with this setup before closing. At first glance, I would assume that this is in no way shape or form an acceptable setup. However, I am not as savy as others when it comes to electrical so I am wondering if this item is the key to making all this work.

http://www.galesburgelectric.com/GE-CR4 ... -4922.html

[Jim Katen]

Looks like a relay system.

- Jim Katen, Oregon

[mthomas1]

New to me. A quick GOOGLE tyrns up"

"Definite Purpose (DP) Contactors are application-specific contactors for repeatedly establishing and interrupting an electric power circuit for application on electric motors used in compressors, fans, andpumps, and resistive heater loads as part of the motor protection system and may be either an integral part of an air conditioning or refrigeration unit or mounted on the control panel for such a job."

"Typical Installation":

[JesseWBryant]

repeatedly establishing and interrupting an electric power circuit

Could the buzzing sound be a result of that?

[Bill Kibbel]

Looks like contactor blocks that I only see in commercial applications - to start and control HVAC, refrigeration and really big motors.

The buzzing sound is likely the electro magnet relay. I don't know if this equipment alone would be to blame for the volt drop.

[chicago]

Jesse did you happen to check the voltage level inside the box?. The reason I ask is in home reference book by Carson Dunlop end of section 4 electrical chapter 5.7 you'll find a section on low voltage lighting controls. It states that in a small percentage of homes is a special wiring system was installed to control light fixtures this system was used primarily in the 1950s and 1960s and employ 12 or 24 V wiring instead of the more common 120 V wiring to control light fixtures it was employed in order to provide additional safety and convenience. This system is somewhat complex and uses a low voltage transformer and a number of relays it did not become popular although it may still be found in some houses. However you stated this was a new model house?

[StevenT]

What everyone says.

I used to see them on commercial washing machines, every day.

When mine used to buzz, I would replace them.

[rlskfoster]

It looks like a contactor setup for a large amount of lights. I would expect this model home had one switch that turned on a lot of interior and exterior lights.

You generally see this in a large open area with lots of flourescents or other types of lights. Power feeds in to one side of the contactor and the switchleg to the lights feeds out the other. When the first employee walks in he hits one switch that energizes the contactor. The contacts, that are normally open, close and power feeds through to turn on the lights. One switch can supply a number of contactors.

Buster

[inspector57]

This is simply two three pole contactors similar to the low voltage contactor in any central air condensing unit.

It appears they have simply run six lighting circuits into the box to turn everything off and on with one central switch. This is not a big cause of concern except when they remove it, there will obviously be splices in this location. My guess is they will leave the box and just remove or bypass the contactors. Everything will need to be supported, clamped, routed like any other circuit or junction box.

Jim

[Terence McCann]

Their 3 phase contactors (L1, L2 & L3)and the L could be interpreted as Load or Line. With the Ts I would imagine that the Ls are Load however, there are 3 wires on the L side and 2 on the T side. What ever is on L2, on the 2nd pic, is dead ended. Just out of curiosity, what as the voltage on L1, 2 & 3?

As Bill stated these contactors are usually found in commercial/industrial applications, no 3 phase stuff in the common residential units.

At best it's a weekend warrior with access to commercial parts.

[inspector57]

More correctly they are 3 pole contactors, no such thing as a three phase contactor to my knowledge. I can't tell the exact attachment configuration, but since this is in a new home, it is doubtful that it is a weekend warrior. My guess is they needed several different circuits and just installed 3 pole contactors rather than six single pole or three double pole.

Jim

[Terence McCann]

Jim, correct 3 pole contactors, normally found on 3 phase circuits for starting 3 phase devices.