Residential Overcurrent Devices

CIRCUIT BREAKERS

Circuit breakers are simply switches that have an internal mechanism that senses an overcurrent in the circuit. This could be caused by overloading the circuit with too many appliances connected and operating at the same time. It could be caused by one piece of equipment or appliance that uses a higher current beyond what the circuit was designed to handle. It could also be caused by a short-circuit. The circuit breaker is designed to trip (open) under these conditions. Circuit breakers are designed to protect persons and property from a possible fire. If the circuit breaker itself is defective and does not open or trip when there is an overcurrent, it could cause a fire. Standards have been set up for satisfactory circuit breaker manufacturing.

When checking circuit breakers you need to check visually and manually the exact position of the switch handles. A breaker is ON when the switch handle is fully in the ON position. A breaker may sometimes look ON but it is OFF. A breaker that looks ON and is somewhat in the midway position is OFF and it needs to be reset. Some breakers after they trip, may need to be reset by switching it in the OFF position first, then switching it to ON. You may touch the handles of the circuit breaker switches and you will not be shocked. The handles of a circuit breaker are insulated; thus carry no electrical current.

PLUG FUSES

Older homes used fuses for overcurrent protection. Today, many older homes are upgraded to circuit breakers. In homes with fuses, screw type plug fuses were used. They were made with glass or the top being transparent. This makes it easy to see if the circuit opened by a burnt and melted fuse link.  Fuses should always be replaced with the proper sized current protection; replace a 15 amp fuse with a 15 amp fuse; a 20 amp with a 20 amp; and so on. The problem with ordinary plug fuses is that you can increase the amp size on a circuit that may not be designed for the increased amp load. This could pose a fire hazard. One solution to this problem is to use Type S fuses. Type S fuses are rejection or tampering resistant; that is, they have a rejection design which offers resistance with tampering with the established branch circuit design by rejecting certain higher amp rated fuses from being inserted in the holder. You insert a properly rated adapter into the fuse baseholder. The appropriate size fuse screws into the adapter. These adapters limit the ampere rated sizes of fuses and will not allow an oversized fuse to be used. Caution: once the adapter is installed it cannot be removed.

Type S Fuse

Type S Fuse

Type S Fuse Adapter

Type S Fuse Adapter

If you want to simply disconnect a circuit, remove the fuse from the baseholder by unscrewing it in a counterclockwise direction.

If it is not noticeable through the transparent material that a fuse link has blown or melted open, you may check the fuse by using a voltage tester. Check that the fuse is firmly inserted by twisting it in a clockwise direction. Next, hold one test lead on the neutral bus bar or adequate ground and with the other test lead touch the screwshell of the fuse or if visible, the corresponding circuit wire terminal (usually, horizontally left or right of the fuse).

CARTRIDGE FUSES

In residences with pool motors, air conditioning or other equipment, cartridge fuses may be used in disconnects or fuse boxes to protect motors, compressors and associated equipment from overcurrent conditions.

 

LP-CC Cartridge Fuse

Another Type of Cartridge Fuse

Electrical Safety Part 2

THE FOLLOWING INFORMATION IS FOR THE PURPOSE OF HELPING A COMPETENT PERSON WORK SAFELY WITH ELECTRICITY. THE TECHNIQUES AND METHODS SHOWN HERE ARE NOT ALL THAT A PERSON MAY NEED TO WORK SAFELY AND THE ARTICLE DOES NOT INTEND TO IMPLY THAT THIS IS COMPLETE FOR ALL WORKING SITUATIONS. IF YOU WORK WITH ELECTRICITY AND ITS ASSOCIATED EQUIPMENT AND USE THESE TECHNIQUES AND METHODS, YOU DO SO AT YOUR OWN RISK.

THINGS TO REMEMBER TO WORK SAFELY WITH ELECTRICITY

1. ALWAYS ASSUME THAT EQUIPMENT OR DEVICES ARE HOT (electric power is ON and is present at the device or equipment).

 2. ALWAYS DISCONNECT, that is, turn off electricity to the devices and equipment that you are going to work on. You can disconnect the electricity by:

  • Unplugging cord and plug connected appliances.
  • Turning or flipping OFF switches on walls or other control devices.
  • Removal of fuses at main or sub panels. Some of these may still be found in older homes or combination switch or receptacle fusible boxes.
  • Turning or flipping OFF circuit breakers at main or sub panels. See article on Residential Overcurrent Devices.

3. Ensure that the electricity WILL NOT be turned on by self or other persons. This can be done in one or more ways.

  • Have someone stay at the location where the electricity is disconnected so that he or she will allow no one to turn the electricity on.
  • Some circuit breaker installations provide a slotted tab for the use of a lockout device at the circuit breaker, allowing no one to operate the breaker switch. In a home, you will probably not have this feature. If you do, a lockout device is a separate item that can be purchased.
  • Orally instruct others not to touch the switch you turned off. Tag the switch “DANGER” instructing others to “DO NOT TOUCH OR DISTURB SWITCH.” However, do not trust in tags alone.
  • Some wall switches can be taped temporarily off with black electrical tape. Only do this if the switch is in view of your work location.
  • Also, always use good common sense. If you are 100% sure that no one will turn the electricity on, then you may safely work on the device or equipment. However, rarely can you be 100% sure. In practice, apply at least two of the aforementioned security procedures and you should be safe.

THE FOLLOWING SHOULD ONLY BE DONE BY SOMEONE MENTALLY AND PHYSICALLY (DEXTERIOUSLY) COMPETENT.

In cases where you cannot trust anyone, you may need to physically open or remove the circuit breaker panel cover and disconnect the hot wire from the breaker terminal. First, switch off the circuit breaker of the circuit you are working on, before disconnecting the wire. A flat head or phillips screwdriver can be used to disconnect the wire. For additional safety measures, you may want to stand on a rubber mat or dry wood for insulation; especially if the ground is damp.

MAKE SURE THAT YOU AND YOUR SCREWDRIVER DO NOT COME IN CONTACT WITH ANY BUS BARS OR OTHER SCREW TERMINALS EXCEPT THE ONE THAT IS CONNECTED TO THE WIRE YOU ARE DISCONNECTING.

Bus bars are what the circuit breakers or fuse baseholders are connected to. Bus bars are HOT and you can receive an electric shock and serious burns if you touch one while you are grounded. You may touch the insulated part of the wire; it does not conduct electric current. You do not have to unscrew the circuit breaker terminal completely to remove the wire. When removed from the breaker terminal, tape the metal part of the disconnected wire with electrical tape; it is not to come in contact with any bus bars or terminals. Carefully move the wire out of the way in the box and reinstall the panel cover. When reinstalling the wire, apply firm pressure to the terminal screw on the circuit breaker, but do not strip it.

4. Test the device or equipment to make sure the electricity is OFF. This applies only to the circuit or circuits which you have disconnected power from. Other devices in the building location may still be hot.

  • You may purchase a voltage tester, which is very convenient to use, and a more accurate way to test. Be sure you read how to use the tester and do not test voltages above the voltage rating of the tester. Do not test fluorescent light sockets with these testers.
  • You may use an appliance that you know is in good working order. For example, you might plug an iron into a receptacle to test if the power has been disconnected from the receptacle. You might use a  portable lamp or a power tool to test the receptacle. If there was no power to the receptacle or outlet to begin with, remove the cover plate and test the terminals of the outlet for the presence of power using a voltage tester.
  • To test a ceiling light switch make sure you use a working light bulb. You may first test the light bulb in another lamp socket to make sure it is working. The switch can also be tested with a voltage tester by removing the switch cover plate and test the terminals of the switch. Place one lead of the tester to ground (ground wire or metal box) the other lead touching the terminal tested.

5. When you return to your work after a break, such as lunch, REPEAT STEPS 1 – 4.

By following these rules to the letter, you should never receive an electric shock by the electric utility service; provided you are working on the side in which the electricity has been disconnected (turned OFF) and that no one overrides the safety measures implemented.

Electrical Safety

Electricity can be very dangerous when handled improperly. Not only can a person die from an electrical shock, but also he can receive serious burns. Loss of property can be attributed to fire because of improper wiring or failure of electrical devices and equipment. Some simple electrical devices and equipment are: circuit breakers, fuses, switches, receptacles, lamp fixtures, small and large appliances, heating, wiring, and associated equipment.

Working with electricity can be safe. The key is to never work on an energized circuit. This, of course, is easier said than done for the fact that electricity cannot be seen, heard, smelled, or tasted. Sometimes, when only the conductor of current is touched, do we know electricity is present. This does not have to be this way.

The following electrical safety tips are written so that the person working on electrical equipment will become more aware of what they are doing so they may do it safely.

Repair Damaged Rigid Conduit Without Union Fittings

TIP: How to repair a backhoe damaged underground section of rigid conduit without union fittings.

First remove all conductors.

Use reciprocating saw to remove damaged section of pipe. Clean the burrs off ends of existing conduits to be mated by reaming with a half-moon or round file depending on size of pipe. Clean off any rust or debris the entire length of at least an inch and a half or two inches from the end of the conduits.

If conduit section removed was bent as damage, the remaining ends cut to be mated should now be able to accommodate a new straight section of pipe or at the least a light bend or kick in the new section if needed.

Cut your section of pipe to install to size after you have made any necessary bends. Make the space tolerance between the existing pipe ends and new pipe ends as small as possible. This will insure the best fit for a properly positioned coupling. If the length of rigid pipe to install is less than 10 feet you will need two appropriate sized threadless compression couplings for rigid conduit.

Midway inside the threadless compression coupling is a “pipe stop” or ridge. You need to remove these on both couplings. This will allow the full length of the coupling to move freely on the conduit. A half-moon or round file works good to remove these stops. Remove the compression rings and nuts before you do any filing.

Slide both couplings on the pipe to be installed. Install new section of pipe by sliding the coupling into place on existing conduit end. Make sure that you center the couplings between the ends of pipe so that the compression rings on both ends of coupling will clinch the pipes completely. If you do not center the coupling properly you could have a compression ring clinching partially the conduit end and partially the dead space between the conduits. This would be a bad installation.

Tighten up all connections. As an added benefit to installation, install black vinyl 10 Mil tape over the coupling and the length of the pipe.

Install new conductors.

Simulating Darkness For Photocell

TIP for activating photocell for testing lamps controlled by photocell.

With power to the fixture turned on, place black electrical tape over the cell to simulate darkness or use a dark hat to cover the cell completely.

Connecting Stranded Wire With Solid Wire

TIP: for connecting stranded wire with solid wire. Sizes #10, #12, #14 wire gauge.

If you have more than one stranded wire to be connected, strip the insulation of all wires and wrap the wire strands together. If connecting these with one solid wire, place all the wires parallel making sure that the end of the stranded wires do not fall below the end of the solid wire, i.e., the ends of all the wires should be even. Install wire connector. If connecting the stranded wires with more than one solid wire, first twist the solid wires together, Twisted wirethen cut the tip of the solid wires diagonally, then place all the wires parallel. The ends of all the wires should be even. Install wire connector. Some electricians find it better not to twist the solid wires when using “wire nut” or “wing nut” type connectors; my experience has proven different. After installing the connector, with one hand hold the wires, with the other hand try to pull the connector straight off. It should not come off with mild pulling force. Try pulling the stranded wires separately. They too should not come off
with mild pulling force.

Make Room For Devices

If your connection box is full and it is difficult to insert the device (switch or receptacle), find out what kind of wire connectors, if any, are used. There is a type called “wing nuts.” If you have this kind, do the following.Wire Nut

After installing the wire connectors on the wires, cut the wings off the wing nut with diagonal cutters or linesmen pliers. Do this as close to the body of the connector as possible. You may be surprised how much easier it is to position the wires inside the box after the wings are cut off. If you have to remove the wing nut later, you can easily do this by grabbing on to the wing nut using linesmen pliers, then twist off.

Seating a Switch or Receptacle Snuggly

TIP: When Switches or Receptacles are recessed too much because of faulty installation of box or plaster ring.

Sometimes in the installation of a device box, a craftsperson may install it too deep in the wall not allowing for the thickness of the drywall or plywood covering. If a metal box is used, they may use a plaster ring too shallow; again not allowing for the thickness of the drywall or plywood covering. As a result of this kind of installation, the device, such as a switch or duplex receptacle may not seat properly when fastened down. In addition, sometimes the tabs on these devices do not seat against the drywall when fastened down because the opening for the device box of the drywall was cut too much.

Switch Receptacle Fix

Correct cutout compared with oversize cutout.

If you find an outlet box that has not been installed properly or the device opening on the wall covering too large, there are at least four things you can do to have the device seat snuggly.

1. You can use an appropriate size metal or plastic spacer over the hold down screw. If you do not have these handy, read on for other methods.

2. This next method is more complex and does not always work given the materials and time to work with. If you have the right type of flat head screw for the device hold-down, this next method might work sufficiently. Unless it has been changed by a maintenance person, the standard size screws are number 6-32. Put the screw in the device hold-down hole or if the screw is already in the device hole, take the paper card that holds the screw off. Take a 6-32 nut and screw it on the number 6 screw that holds down the device. Screw the nut all the way, it should not put pressure on the device itself. If it does you will not be able to screw the screw to the box. For the ideal, there should be some light play or slop so the screw has movement. If this cannot be achieved, move on to the next method. Take another 6-32 nut and screw in on the screw. Adjust the nut on the screw to the proper distance needed so that the device does not sink into the wall when screwing the screw. You may need to do this process with both screws that fasten the device to the box. If the nut turns while screwing in the screw the purpose of the nut will be defeated. You can carefully crimp or cut a groove on the screw diagonally across the threads. This will prevent the nut from moving any further than desired while screwing in the screw. The threads of the screw have to be cut exactly where you want the nut to stop.

3. This next method is less complicated and will work well if you have the parts. With the device 6-32 hold-down screws, use a combination of oversize nuts like 8-32 as wide spacers and small flat washers. You can also use a 6-32 nut to hold them in place. The washers work well to make fine adjustments to length.

4. With this next method you make your own spacer. Take  #12 insulated soft drawn solid copper wire and wrap a length of it around the screw. Soft drawn copper wire is easier to bend and work with. Keep the insulation on the wire. It may be easier to first form the wire, then slip it over the screw without taking the screw off the device. Form the wire longer than needed, install on screw, then cut to proper length with diagonal pliers or cutters.

With all these methods, make sure your device is grounded properly. Some of these methods may compromise a good ground. In this case use a bare or green insulated copper wire attached to the device’s ground screw and proper ground. It just takes some practice to see which method works best for a given situation. Give it a try.

Tell Me About Surplus Fuses

Here is information you need to know about overstock, oversupply, or surplus fuses that are new, nos, and used. This information could save you a significant amount on your fuse purchases.

How fuses are described by the distributor is important for the purchaser in making informed decisions. It is especially important for the surplus fuse supplier that their descriptions remain consistent. The following is the standard for Alan’s Sales.

The word surplus sometimes carries the idea of products being cheap, unreliable, or inexpensively manufactured. But this is just not true if the surplus fuses are named brand. If you purchase a named brand fuse you are getting the same product whether it is surplus or otherwise. With surplus new or new old stock (NOS) fuses, they are simply new and not used. That is, they have not been energized to carry an electrical load.

With a used fuse or those that are shop worn, these blemishes or conditions have no effect on the reliability and performance of the fuse. The interesting fact about fuses is their reliability relative to time.

There are no moving parts, so with a NEW or NOS fuse there is no wear or tear to the product, except for handling, such as in storing and for a USED fuse, handling, installing and removing the fuse – that’s it!

According to Ferraz-Shawmut (Mersen) a leading fuse manufacturer, “The speed of response of a fuse will not change or slow down as the fuse ages. “In other words, the fuse’s ability to provide protection is not adversely affected by the passage of time.” (The Advisor-Application Information, 10 Reasons For Using Current Limiting Fuses)

On occasion, some NEW or NOS fuses may look used, shop worn, or even dirty. The appearance of the fuse does not affect its performance. From a practical sense, it does not really make a difference what the fuse looks like when you install it and put it to work? However, with Alans Sales not all surplus fuses are bad looking. In fact, Alan’s Sales has some pretty good looking USED fuses at some better looking prices. However, the appearance is not guaranteed. Remember, it is the technical and performance aspects of the fuse which serve the purpose in overcurrent circuit protection.

Whether you are purchasing NEW, NOS, or USED fuses, only purchase fuses from dealers who will stand behind their product with a fair refund/exchange policy. Also check out Alan’s Sales high standards for fuse quality control.

Faster Metal Drilling

TIP: Make drilling into mild steel metal boxes, cans, and fixtures easier and faster.

I find that using any kind of petroleum based oil applied to the tip of the drill bit or hole saw speeds up the cutting of the hole. For larger size holes reapply the oil when the cutting slows down. Always use a sharp drill bit.