Electrical Questions

My insurance company recently sent me a letter asking us to upgrade our electric service size to a 100 amp service. They state in the letter that a previous owner reported that the house has a 60 amp service. I called in a friend who knows a few things about electricity and he says the service wire coming into the panel is a 60 amp wire but the breaker and the electric panel are both rated at 100 amps. It seems to me that because I have a 100 amp beaker and panel I have a 100 amp service. So what do I tell the insurance company?Unfortunately, you have a few problems. The first is with the safety of your system. For instance, because you have a main breaker and electric panel that are rated to carry 100 amps, your branch circuits could readily draw 100 amps through the branch circuit wires in your system. The problem is simply that your service wire supplying the main panel can only safely carry 60 amps. If more than 60 amps are drawn through this main service wire it could overheat and fail, causing a fire in the 60 amp wire feeding your panel. As well, if your service wire runs inside the exterior wall of your house, an overheated service wire could ignite a fire in this wall.

The second problem you may encounter is with your insurance company. They are correct to say that this is a 60 amp service. The reason is simply this. The size of your electrical service is determined by the size of the breaker or the service wire, whichever is smaller. Therefore, you have a 60 amp electrical service.

You could easily reduce the risk of fire and improve the overall safety of your electrical system by having a qualified electrical contractor change your main breaker from 100 amps to 60 amps. This will likely bring your system into compliance with Electrical Code specifications. However, your insurance company may still want you to upgrade the size of your service to 100 amps. This can only be accomplished by replacing your 60 amp service wire from the hydro pole to your distribution panel. Also, because the new 100 amp service wire has a bigger wire diameter, you will likely require a bigger service mast and conduit. Unfortunately, none of this work is the responsibility or domain of the public utility service provider. Therefore, you will need to hire a qualified electrical contractor to make these changes to your service if the insurance company requires this upgrade.

I have an old heritage house that I am insulating in stages. I found strands of wire running through the ceiling joists. Is there anything I should be concerned about?From your description these wires are most likely older electrical service wires called Knob and Tube wiring. They can be identified by ceramic knobs and tubes used as terminals and protection through joist holes. This type of wiring used until the 1950s is usually still reliable. However, if you find wires that have been spliced to newer “Loomex” wiring, the original wiring may not be as reliable and safe.

Be sure not to bury the Knob and Tube wiring in insulation. Although there is some debate about this subject, it is generally accepted that this type of wiring works best when the heat build up in the wiring can dissipate unrestricted to the surrounding air. As well, some insurance companies are now reluctant to underwrite new insurance policies on houses with Knob and Tube wiring even though the system may be safe. This comes about with usually with change of ownership on the building.

I own a duplex with two older electric fuse panels. The tenants have been replacing small fuses with bigger fuses and I am concerned that this could be a problem. Is there any way I can control this situation?You are absolutely right that this is a problem that you should control. Over-fusing a branch circuit can lead to an electrical fire. Unfortunately, it is hard to educate every person living in your building about using the correct fuse for the branch wire size. However, you can purchase fuse rejecter washers that will restrict the size of the fuse that fits in the corresponding fuse holder. In other words, with a fuse rejecter screwed into the fuse socket no one can install a larger fuse than required in that opening. There are also “Type S” fuses available designed to prevent the wrong fuse from being introduced as circuit protection.

When purchasing fuses, look for type “Type P” fuses. They are designed to sense high temperatures around the fuse and blow even though the current draw is low. Appliances with large electric motors like refrigerators and freezers should be fused with “Type D” fuses that permit extra current to flow on a demand start-up without “nuisance” blowing the fuse. This will help limit the number of times your tenants need to replace fuses. Fortunately, for the safety of you and your tenants most modern fuses are designated “Type D and Type P”.

We own an older heritage home and most of the electric receptacles are two prong outlets. Are there any issues we should be aware of concerning these outlets?It is quite common to find two prong grounded and ungrounded outlets in homes built before 1960. Whether these outlets are unsafe is a matter of discussion. First, you should purchase an inexpensive two-wire outlet tester to determine if the outlet box is grounded or ungrounded. There is a potential safety hazard if the box is not grounded because a loose hot wire or terminal from the outlet can contact the metal box. The live box will now become a shock and fire hazard. Don’t just replace a two slot receptacle with a modern three prong grounded outlet. This will provide a false sense of security to any user who would assume the outlet is grounded.

However, you can install a ground wire for the receptacle. It may be connected to a nearby water pipe or carried back to the main electric panel. You can also replace the outlet with a GFI receptacle. This is not as good as a fully grounded circuit because in some circumstances you can still get a very brief shock before the GFI interrupts the circuit. With a fully grounded circuit you will not get any shock. Still, a GFI outlet is better protection and often easier to install than a fully grounded circuit. Remember that any appliance (including computer equipment) that comes equipped with three-prong plug relies on the grounded outlet to function safely. Home computers for example, dissipate static charges through the ground wire. The GFI solution will not help in this case because it is not a grounded outlet. Consider consulting with a certified electrician if you are in doubt about the ground requirements for certain appliances. A tradesperson may recommend installing some fully grounded branch circuits if you.

Recently I submitted an offer on an older house in Castlegar. The insurance agent I deal with wants to know the approximate age of the wiring in this house before his company will insure the building and contents. So I’ve opened my electrical panel box and looked at the wiring. Some of it looks older than the rest. Is there any way I can answer his question just by looking at these wires?The good news is yes, anyone can figure out the approximate age of the wiring in his or her house if you have some basic information. All building wiring since early on has been covered with an insulating protective coating. This coating is the key to identifying the age of a particular wire. For instance, the earliest type of home wiring called “knob & tube” was sheathed with rubber. All house wiring since then has been encased in some type of casing to prevent the neutral, hot (and ground wires in modern wiring) from touching each other. Each type of casing is commonly connected to a particular time period. So here is the list of time periods that can be relied on to provide the approximate age of the wiring in your home.

Knob & Tube: rubber casing 1920 – 1950 (also identified by their distinctive porcelain knobs & tubes supporting the branch wiring.)

Two or three wire cables with no ground wire – 1945 to early 1960’s

Cloth Sheathed: two or three wire with an integral ground wire – Early 1960’s to early 1970’s

Cloth sheathed aluminum wire with an integral ground: – 1964 to 1978

Plastic sheathed aluminum cable with an integral ground wire: – 1974 to 1978

Plastic sheathed copper cable with an intragal ground wire: – 1974 to date

Be cautious when opening your electric panel. Remember your dealing with a potential killer. Consider completing this investigation in the company of a qualified electrician. Happy sleuthing!

I have just rented a home in Castlegar and discovered several outlets throughout the house and garage with three openings that won’t accept a standard three-prong plug because the outlet openings are t-shaped. What is the intended use for these receptacles?You may have noticed that the outlets for your electric cooking range and clothes dryer are both different from the other outlets in your house. Because we don’t routinely plug and unplug fixtures in these outlets it is readily apparent that these outlets and other outlets in some houses will not accept a “normal” three-prong plug.

These outlets and their branch circuit wiring have a unique configuration because they are designed to handle higher amounts of amperage required to operate electrical equipment that demands more than a “normal” 15-amp outlet can provide. For instance some 20-amp receptacles have a neutral slot set at right angles to the hot slot. Conventional plugs will not fit into these slots. Some outlets have one t-shaped slot that will accept either 15 or 20 amp plugs. Some jurisdictions now require new homes to be equipped with one or two of these 20-amp circuits. Often these circuits are located in kitchens and dining rooms. Another common place to find one of these higher amperage outlets is in a workshop or garage where the previous owner may have installed the outlet(s) and heavier gauge branch circuit wiring to run a welder, compressor or other large demand workshop industrial equipment. Remember that these “unconventional” outlets are rated for larger amp loads and should not be installed on wiring that is designed for 15-amp circuits.

The house I purchased last year was constructed in 1972. A neighbour whose house is the same age told me I have aluminum wiring that can be a fire hazard. Is this true? If so, is there anything I should be doing to avoid problems?Many houses constructed between 1964 and 1978 came equipped with cloth and plastic sheathed aluminum wiring. You should have an electrician confirm this because aluminum wiring can be easily mistaken for an older type of solder dipped copper wiring. Here’s a tip. Aluminum wiring can be distinguished by the bare aluminum grounding conductor and the word ALUMINUM or ALUM or AL on the sheathing.

Aluminum wiring was introduced in the 1960’s because it was a less expensive alternative to copper wiring, even though larger wire gauge sizes were required and it was not as good a conductor as copper. Some problems associated with aluminum wiring are that the wire tends to creep out from under the terminal screws, the wire can oxidize reducing conductivity, and the wires can be easily damaged during installation. Several house fires were attributed to this wiring as a result of these deficiencies. Industry then responded to these concerns by designing connectors, receptacles and switches better suited to this wiring. Not all houses were retrofitted with this hardware so you should confirm that your receptacles, switches, connectors and fixtures are labeled CUAL and / or CO/ALR. The latter designation was introduced in the early 1970’s and used tin-plated terminals. This hardware more effectively controlled over-heating problems than the earlier CUAL hardware.

As well, if your home is equipped with aluminum wiring you should check for aluminum compatible equipment at the main panel. First, you or your electrician can check that the panel and circuit breakers have the aluminum designations (CUAL). There are even specially designed aluminum wire twist-on connectors, which continue to create controversy concerning their safety. These wire nuts are not easily identified, so again, consult your electrician. In the main panel all larger stranded wires in contact with terminals should be coated with an anti-oxidant paste to prevent aluminum oxide from forming where the aluminum comes in contact with the air.

If you have aluminum wiring here are a few tips. Watch for signs of overheating especially at receptacles that are used for large demand appliances like clothes dryers, hair dryers and portable heaters. Have your local electrician do a detailed inspection, including a review of circuit wiring for loose wires at terminals. In the big picture, aluminum wiring can be safe if it has compatible receptacles, switches and fixtures and the wiring is maintained and serviced regularly.

I had the cover plate off my electric panel because I was adding a branch circuit wire for more outlets in my workshop. But I noticed that three bare copper ground wires were connected to the same bar as the white neutral wires. All the other copper ground wires in the panel were twisted together and connected to a different bar in the panel. Is it okay for those ground wires to be there or are they serving a different propose than the other ground wires?You have definitely picked up on a common mistake in electrical distribution panels. Often this is an error made by homeowners doing some weekend wiring. The uninsulated copper ground wires in the circuit branch wiring should never be connected to the neutral bus bar in a panel. For instance, the neutral (usually white) wire carries electricity that was not used by the appliance back to the panel. So this wire is actively transporting electricity in the branch circuit.

The circuit ground wires should be idle and should be used to carry current only in emergencies. When you connect these ground wires to the neutral bus bar, the ground wire is more likely to carry everyday household electricity instead of emergency power from situations like short circuits. So, its’ ability to handle these emergencies is diminished. As well, since the ground wire is a bare wire people don’t expect it to be carrying electricity. So there is a potential for shock. The bare copper ground wires in branch circuits are connected to outlet boxes and equipment cases. If these ground wires are bonded with the neutral wires at the panel, the outlet boxes and equipment cases can become energized, which can also lead to shocks.

The simple solution is to shut off the main power to the building and then remove the ground wires from the neutral bus bar. Relocate them on the panel ground terminal where they belong. Whenever these types of problems are detected in a panel, it is a good idea to get a qualified electrician involved in the repairs. Often when you see ground wires that are located on the neutral bus bar, other problems also exist. So while the electrician is present, ask the person to look for other potential wiring problems like over-sized breakers, circuit wires crossing over the main bus bars, double taps and bonding issues.

I bought an older home in west Trail two years ago. I want to put a hot tub in our backyard. So, yesterday I looked at the main electric panel to see if I had room to add a 40 amp breaker. To my surprise the 70 amp main panel is full and I found a weird box on the side of the panel that has a label “load miser”. What is it? Can I still add an extra breaker somehow?From your description it seems very unlikely that you have enough electrical capacity to provide an additional 40 amp circuit for a hot tub. For instance, your 70 amp panel is full. You could possibly extend the service with a sub panel but this is quite unlikely, especially if you have an electric stove, clothes dryer and / or hot water tank. All of these appliances demand considerable current and any combination of them with a hot tub would likely overload a 70 amp service.

Another indication of your electrical capacity is the fact that your home is equipped with a “load miser”. Often, when a house lacks sufficient 240 volt circuits in the main panel for the number of major appliances in the house, a load miser is installed. This usually indicates that the electrical capacity in the house is marginal for the number of major appliances in use. For example, commonly, a clothes dryer and an electric hot water heater are served by their own dedicated 240 volt circuits. In your home it is likely that they share the same circuit with a single 30 amp breaker and a single 10 gauge wire.

The load miser is a switching devise that supplies current to one of these two appliances at a time since there isn’t enough current carrying capacity in the 10 gauge wire to operate both appliances simultaneously. Therefore, the load miser gives one of the appliances priority. The load miser cuts off power to the non-preferred appliance when the current flowing through the miser reaches 80% of the upstream fuse or breaker rating.

For instance, in the example of the hot water tank and clothes dryer, the hot water heater may be drawing power most of the time. But, when the clothes dryer is in use, the load miser will cut electrical flow to the hot water tank and supply only to the clothes dryer.

It is very unlikely that you will have enough electrical capacity to heat a hot tub given that there are apparently not enough circuits or capacity for your existing appliances. You may be faced with an upgrade to your electrical service. This will probably entail installation of a new 100 amp service wire and main panel. However, before you begin this project, I recommend that you consult with a certified electrician who will be able to assess your electrical loads and corresponding service size.

What causes the buzzing or humming sound that comes from my electrical panel? There was no problem originally, but now the panel hums from time to time -which can be quite annoying, since it is in my kitchen. I have a 125 Amp main breaker and the house is wired up to capacity but not over capacity for a 125 Amp main. Although it is difficult to tell, I believe it is the main breaker that hums, and it does this even when the electrical load is relatively light. For example, in the summer, there is no electric heat on, but the clothes dryer, or range – or sometimes even the fridge or toaster – will start the music happening.Although uncommon, main electric panels have been known to break into full Broadway chorus renditions of “Cats”. Thankfully, your panel is still limited to an occasional hum. And, fortunately, there are some possible causes and solutions that you may consider.

The least likely source may be a small low voltage transformer attached to or near your main panel. The most common of these would be a doorbell transformer. Look for a small metal box with light gauge wiring running from and to it. These transformers often hum, but this is not the most probable source of the annoyance.

A more likely source of the problem is a loose breaker. Often, the contact point between a main or circuit breaker and one of the power supply buss bars will loosen and a small gap will occur between the two contact points. The gap or loose contact point will hum when electricity flows across the contact points. There is a possible simple cure for the problem. Open the panel door when you hear the humming. Do not remove the main panel cover. You will be looking at the main and circuit breakers. With your finger on a breaker, press each breaker in turn pushing it toward the back of the panel. If the humming stops when you press a particular breaker, you have found the loose contact point.

However, if the humming continues after you release pressure on the breaker, the contact points on the breaker or the harness that holds the breaker is worn to the extent that new a breaker, breaker harness or buss bar(s) may be required. If the humming cannot be eliminated by simply pressing on the breaker, I suggest that you contact a qualified electrical contractor for any further investigation because loose contact points and loose wires attached to breakers can cause short circuits and electrical fires.