Tip & How-To about Electrical Supplies

Regular switching and switch loops

A switch loop is a technique that is often used in home wiring to cut back on wire used and to make the circuit less complicated. In a normal switching circuit power comes into the switch box with the white wires tied together and black wires on the switch and then continues to the lighting box where black is connected to black and white is connected to white. With a switch loop the power starts at the lighting box in the black wire that does not go to the switch. That black wire is connected to the white wire that goes out to the switch (note the white wire must be taped with a small piece of electrical tape to show that it is now a powered wire). At the switch both black and white wires must be connected to the switch (the white wire here must also be taped). So now back at the light box you should have two wires. A white wire from your incoming power cable and a black wire from your switch cable. Now all you need to do is tie black to the black of your light and white to the white of your light (note: if you have terminals, white goes to the silver terminal and black goes to the brass terminal.) The wiring is done in this manner because in electrical work black and white make a light, and the the colors are never mixed up because it allows the next person to diagnose any problems much easier.

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Instaling a new pilot light assembly inBryant 234B boiler. The wires to the emergency shut off are not color coded in wiring diagram. Does it matter which wire (only 2 wires)goes where?


Hi Anonymous.
An emergency shut-off loop will almost always be set up so that the circuit is closed during normal operation, with a press of the emergency off button breaking, or opening the circuit. It's set up that way so that if a wire in the emergency circuit breaks, or gets disconnected, the system will shut down, rather than allow operation where the emergency off won't work.

Functionally speaking, if you only have two wires to the switch/button, then which way you connect them won't matter, since the switch will complete the circuit regardless of which way you flow the current. From a Code and consistency standpoint, one of the wires will be ground, and one of them will be hot. Most switches have leads indicating ground and hot on them, and you should be consistent with that. If nothing else, if someone else is later servicing or replacing the switch, also not knowing which wire is which, then they have less risk of mistaking a hot wire for a ground and getting zapped.

Depending on the setup, and whether it's AC or DC on the loop, you should be able to use either a voltmeter or an electricians hot-wire-detector to tell which lead is the hot lead.

Hope this helps, and good luck!
D

Nov 19, 2015 | Electrical Supplies

2 Answers

How can you tell if the protection wire loop is bad?


Your protection circuits are usually wired in series so that if any one of them is open, current will not go to the starter and ignition circuits.
U seem to know what you are doing so just bypass the loop and see what happens. If item starts then that loop circuit is defective. If it still does not run then your issue is elsewhere.

Oct 06, 2015 | Garden

2 Answers

Why does the gate open on its own during the day with nobody home?


If the gate uses a remote control, someone may be cruising the neighborhood with one of the same type trying to find a house to burglarize.

May 30, 2015 | Home Fencing

2 Answers

can't get my switch to operate the outlet just bought a 5625 switch i have two wires coming out of the wall i want to plug a light in the outlet and have the switch control the power to the outlet.


  • Turn off the power to the receptacle that will be replaced by switching off the circuit breaker in the fuse box. Check that the battery is good in a circuit tester. If not, replace the battery. Place the tester's two ends in one set of the receptacle's slots, then the other set. The light on the tester should not come on. If it does, the correct circuit breaker has not been switched off.

  • 2

    Take off the receptacle's face plate by first removing its screw. Detach the two screw securing the receptacle to the box and pull out the receptacle. Loosen the receptacle's terminal screws and pull away all wires from the back of the receptacle. Take out the receptacle (if working properly, it can be reused). If the ends of the wires are chewed up after removing them from the existing receptacle, cut them off with wire cutters. Strip off 1/2 an inch of insulation from the ends, using wire strippers. Bend them into loops with the pliers.

  • 3

    Bend the copper ends of all wires into a loop, using a pliers. Connect the white wires to the silver terminal and tighten the screw to the wires. Connect the black wires to the gold terminal and tighten the screw to the wires. Connect the bare ground wires to the ground terminal and tighten the screw to the wires.

  • 4

    Push all cables into the back of the box, followed by the receptacle. Attach the receptacle to the box with the two screws. Hold the new faceplate in position and install the screw. Turn on the power at the circuit breaker.

  • HOPE THIS HELPS YOU...Jim...Please leave a comment

    Feb 13, 2011 | Leviton Electrical Supplies

    9 Answers

    Alert chipset heat sink not detected system halted error message


    This is a relatively common problem in the Dimension 4600c. The small, fan-less heatsink for the Northbridge chip (a memory/video-to-cpu communications chip) is held down by a spring, which is anchored by two small wire loops soldered to the motherboard at locations marked "HS2". The spring completes an electrical circuit between the two wire loops. The spring puts a substantial force on the minscule bit of solder holding the loops to the motherboard, and was a poor design.

    If a loop breaks off, the circuit is broken, which tells the BIOS that the heatsink fell off. To fix this, you need to 1) secure the heatsink to the chip, and 2) reconnect the circuit between the two "HS2" locations on the motherboard. I have sucessfully used this solution. This solution will not necessarly stand up to a lot of abuse if the Dimension's enclosure is frequently opened and closed to replace other components such as RAM and hard disks.

    0) unplug the computer.

    1a) Recover the heatsink, spring, and loose wire loop. Discard the spring. Get:
    - a fresh tube of thermal paste from Radio Shack or other electronics supply store,
    - some epoxy,
    - a round toothpick,
    - about six inches of insulated 14 to 20 gauge solid copper wire,
    - electrical solder, flux, and a soldering iron,
    - and a box of cotton swabs.

    1b) Using pure alcohol and lots of cotton swabs, clean *all* of the existing thermal paste off of the Northbridge chip and the bottom of the heatsink. When both are dry, apply a dab of paste to the center of the Northbridge chip. Use a round toothpick like a kitchen roller to spread the paste evenly across the small raised center square of the chip.

    1c) Apply small daps of mixed epoxy just outside of the four corners of the raised center of the Northbridge chip. Place the heatsink onto the Northbridge chip, centering and squaring it as best you can. Press firmly to make good contact with the thermal paste. Allow epoxy to dry.

    2a) Firmly seat one or both detached wire loops into their mounting holes at the "HS2" locations. While pressing down on the loop, apply a small dab of epoxy to one end of the loop to secure it to the motherboard. Allow epoxy to dry.

    2b) Strip the ends of the copper wire, and bend the wire so that it can reach around (rather than over) the heatsink to the two wire loops. Solder the ends of the wire to each loop. Knowing how to solder is an exercise left to the reader. "Use head main ting": don't drip solder onto the motherboard.

    You can now plug in the computer and restart. The BIOS and/or OS may have saved the error state and return a different message about the heatsink issue. You may need to reboot a couple of times to allow the BIOS to notice that the "HS2" circuit is (hopefully) now complete. When you've sucessfully booted the machine, shut it down and gently close the Dimension's enclosure.

    May 21, 2008 | Dell Dimension 4600C PC Desktop

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