Northbay Electrical Services

2010-04-11T21:07:00.000-07:00

Most basic troubleshooting calls including repair and installation calls are resolved less than $500. We have developed this list to serve as a guideline and to provide "ball park" estimates for common items. These costs are for a typical small to medium house in California. Difficult access and other factors could increase cost substantially. Please note: Recent construction cost increases may make some of these prices lower than you will find locally.

ELECTRICAL

Replace existing switch or outlet $35 typical
Replace existing outlet with GFI outlet $65 [add $15 for exterior]
Install new Ceiling Fan/ chandelier $450 typical

w/existing switch

Safety Survey & Correction $450 typical
New remodel lighting/power outlets: $400 typical

$150 for each end of the residential wire.
$200 for the commercial.

Replace existing Lighting Fixture $55 typical
Correct reverse polarity $50 [device only]
Bathroom Remodel starting from from $400
Kitchen Remodel starting from from $1,000 [size & finishes]
New120-volt circuit starting from $300 [wire path & length]
New 240-volt circuit starting from $500 [wire path & length]
New Subpanel from $600
Upgrade fusebox to 100amp panel from $1,800
Upgrade small panel to 200amp main $3,000 typical
Bring home Grounding System to compliance $400 typical
Residential Service Call $125 first hour, $65/hr thereafter
Commercial Call $150 first hour, $85/hr thereafter

Don't Try this at Home

2010-03-15T09:46:00.000-07:00

Maintain Electrical Safety
The insulation on electrical wires can become damaged by wear, flexing, or age. Some clues that you may have an electrical problem are:

Flickering lights. If the lights dim every time you turn on an appliance that circuit is overloaded or has a loose connection.
Sparks. If sparks appear when you insert or remove a plug, that could be a sign of loose connections.
Frequent blown fuses or broken circuits. A fuse or circuit breaker that keeps tripping is an important warning sign of problems.
Frequent bulb burnout. A light bulb that burns out frequently is a sign that the bulb is too high a wattage for the fixture.
Avoid the use of extension cords.

Aging happens but fires don't have to...

ARC FAULT CIRCUIT INTERRUPTER

All 120-volt, single phase, 15 and 20-ampere branch circuits supplying outlets installed in dwelling unit family rooms, dinning rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, or similar rooms or areas shall be protected by a listed arc-fault circuit interrupter combination type.

AFCI – a new type of circuit breaker that recognizes potential fire hazards and immediately shuts off the power.

Top Causes of Arc Faults

Loose or improper connections, such as electrical wires to outlets or switches
Frayed appliance or extension cords
Pinched or pierced wire insulation, such as a wire inside a wall nipped by a nail or a chair leg sitting on an extension cord
Cracked wire insulation stemming from age, heat, corrosion, or bending stress
Overheated wires or cords
Damaged electrical appliances
Electrical wire insulation chewed by rodents

Electrical Outlets Safety

2010-03-12T09:56:00.000-08:00

TAMPER-RESISTANT RECEPTACLES
All 15- and 20-ampere receptacles in a dwelling unit shall be listed tamper-resistant.

...Going against all the fire safety training I’d gone through growing up, I grabbed an industrial extension cord and power strip from the garage, and ran it through the dining room into the den. I finished setting up my laptop around 2 a.m. and went to bed.... ...After that, I got kind of lazy. I knew that I had to deal with the electrical problem, but I was dreading what it would cost to have an electrician come fix it. We lived with the extension cord running across the floor for about a week, hoping that no one would decide to drop by unannounced...

How many things can you plug into an electrical outlet before it catches fire?

2010-03-10T09:58:00.000-08:00

What causes humming in audio systems?

2010-03-08T10:01:00.000-08:00

Some articles claim that wiring and grounding problems account for up to 80 percent of all power quality related problems related with sensitive electronic equipments like audio/video systems.

How OK is it to replace ungrounded outlet with GFCI outlets?

2010-03-06T10:03:00.000-08:00

Q2. Under what condition can a two-wire receptacle be replaced with a three-wire receptacle, when no ground is available in the box?

A. Where no equipment bonding means exists in the outlet box, nongrounding-type receptacles can be replaced with [406.3(D)(3)]:

Another nongrounding-type receptacle.
A GFCI grounding-type receptacle marked "No Equipment Ground."
A grounding-type receptacle, if GFCI protected and marked "GFCI Protected" and "No Equipment Ground."

Note: GFCI protection functions properly on a 2-wire circuit without an equipment grounding (bonding) conductor, because the equipment grounding (bonding) conductor serves no role in the operation of the GFCI-protection device.

CAUTION: The permission to replace nongrounding-type receptacles with GFCI-protected grounding-type receptacles doesn't apply to new receptacle outlets that extend from an existing ungrounded outlet box. Once you add a receptacle outlet (branch-circuit extension), the receptacle must be of the grounding (bonding) type and it must have its grounding terminal grounded (bonded) to an effective ground-fault current path in accordance with 250.130(C).

The following vid shows a bad switch.

2010-03-03T10:04:00.000-08:00

Smoke detector requirements

2010-02-27T10:10:00.000-08:00

Smoke detector requirements as stated in the 1994 UBC
310.9.1.4 Location within dwelling units. In dwelling units, a detector shall be installed in each sleeping room and at a point centrally located in the corridor or area giving access to each separate sleeping area. When the dwelling unit has more than one story and in dwellings with basements, a detector shall be installed on each story and in the basement. In dwelling units where a story or basement is split into two or more levels, the smoke detector shall be installed on the upper level, except that when the lower level contains a sleeping area, a detector shall be installed on each level. When sleeping rooms are on an upper level, the detector shall be placed at the ceiling of the upper level in close proximity to the stairway. In dwelling units where the ceiling height of a room open to the hallway serving the bedrooms exceeds that of the hallway by 24 inches (610 mm) or more, smoke detectors shall be installed in the hallway and in the adjacent room. Detectors shall sound an alarm audible in all sleeping areas of the dwelling unit in which they are located.

Why does polarity matter, anyway?

2010-02-25T10:15:00.000-08:00

Is there any danger? Contrary to what many people think, reverse polarity can also be a serious safety concern. Consider a light fixture with no bulb. If wired correctly, the only live part is the button at the base of the socket. A person is much less likely to touch this button than the threaded collar around the socket. If wired with reversed polarity, it is the threaded collar that is live! If you inadvertently touch the metal base of the bulb while it was in contact with the socket I can receive a severe shock.

Switched Appliances - Polarity matters with appliances that have switches. When the appliance is plugged in, power should only go as far as the switch. If polarity is reversed, power will go through the entire appliance back to the switch. If a wire comes loose in the appliance, the entire case of the appliance may be electrified, even though the appliance is not on. This is a shock hazard. Reversed polarity outlets often go unnoticed for a long time. Many appliances will work just fine.

They don't make that anymore...

2010-02-23T10:17:00.000-08:00

Notice the center meter socket, the lower left corner has been lost to heat from arcing.

What constitutes Acceptable Flicker?

2010-02-21T15:48:00.000-08:00

Brownout

Flickering lights. If the lights dim every time you turn on an appliance that circuit is overloaded or has a loose connection.

Your wiring should be thoroughly inspected starting at the incoming service conductors and continuing through each outlet or junction box to insure that a proper neutral path has been established for each circuit, and that all connections are tight. I have fixed this problem hundreds of times in homes here in San Anselmo.
The Facts : December is the most dangerous month for electrical fires. Fire deaths are highest in winter months which call for more indoor activities and increase in lighting, heating, and appliance use. Most electrical wiring fires start in the bedroom.
The Cause: Electrical Wiring

Most electrical fires result from problems with "fixed wiring" such as faulty electrical outlets and old wiring. Problems with cords and plugs, such as extension and appliance cords, also cause many home electrical fires.
In urban areas, faulty wiring accounts for one third of residential electrical fires.
Many avoidable electrical fires can be traced to misuse of electric cords, such as overloading circuits, poor maintenance and running the cords under rugs or in high traffic areas.

Prevent Electrical Problems
Studies of electrical fires in homes show that many problems are associated with improper installation of electrical devices by do-it-yourselfers. Common errors that can lead to fires include the use of improperly rated devices such as switches or receptacles and loose connections at these devices. Both can lead to overheating and arcing that can start fires. Fires are still caused by people using the wrong size fuse or even putting a penny behind a fuse when they don't have a spare. These practices are very dangerous. Electricity and water are a bad combination. All electrical devices installed outdoors should be specially designed for outdoor use. Outdoor receptacles as well as those in kitchens, bathrooms, and anywhere else near water should be the ground fault circuit interrupting type (GFCI).

I hit this type of problem all the time. There are two types of electricians; the first is learned in troubleshooting and the second in new construction. You apparently got the latter. First the dimming is obviously being caused by low voltage. If it happens when a heavy load goes on then that gives you a good idea of where to start. Here is the procedure you go through to find the problem.
1. This question must be answered: Is the low voltage across the entire house, an entire phase, a single circuit, or part of a circuit? Once you can answer this question, you are on your way to a solution.

2. Put a multimeter on the two hot legs coming into your main--cycle a heavy appliance and see if the voltage lowers significantly. Then measure neutral to each hot leg and see if it lowers or goes unbalanced (one side goes high and the other goes low). If it goes unbalanced it is a neutral problem between the box and the transformer. If the 240 goes down evenly (both legs go down the same proportional amount) it is probably a transformer problem--too small a transformer or an old transformer being used. If one leg goes down and the other stays put--there is a problem with that one leg from the transformer to the panel--normally a bad splice. I've also had this problem with tree limbs rubbing into and shorting (semiconductor) the lines to ground.

3. If everything is good going into the main breaker, then do the same check in reference to the other side of the main--probes to each bus. This checks your main. If the voltage on the buss is good then check on the output of the breaker of the circuit in question. If that is good, then you have isolated the problem to within the circuit itself. Now you have to figure out what part of the circuit is bad. Is it a bad splice, damaged wire (staple too tight) or did the installer used those damn push-in connections?

Have a qualified electrician remove the main breaker at your service and examine the clips that secure it to the buss work, and the buss work itself.

Try to have a separate branch circuits for large home appliances.

No. 1 I have found that the problem lies in the connection of the "Grounded Conductor connection" or the "Neutral connection". I have seen this connection be located, in the first junction box of a lighting circuit, in the neutral bar in the panel, or even at the light itself. Your problem sounds as though it is widespread.

The light flickering problem can be caused by several things, but most probably due to loose or improper neutral connections. The browning out effect is due to voltage drop caused by in increased load on the phase conductors. If the system were properly wired, the browning effect would be minimal, and hardly noticed. When a load imbalance occurs (a 120 volt appliance starts) the increased resistance caused by loose or improper neutral connection is magnified, in extreme conditions the lights will flicker as the connection begins to fail. Your wiring should be thoroughly inspected starting at the incoming service conductors and continuing through each outlet or junction box to insure that a proper neutral path has been established for each circuit, and that all connections are tight. If your house is new your home warranty should cover it, but you will have to fight to get them to spend the time and money to fix it.

I have fixed this problem hundreds of times in homes here in Arizona over the last 26 years, and I can assure you that the problem can be found.

Start by checking your voltage as close to the source as possible (like at the meter base) when the A/C or heat cuts on.

it could be faulty equipment where the motor on the appliance is drawing more than the full load current. To check this out, one can put an ammeter on the service wires and make sure it is not drawing more than 80 %. If so, it is undersized.

First, there is a loose/poor electrical connection somewhere in the system, or the supply from your Public Utility is faulty.

I'd check for loose connections on the phase conductors or the grounded conductor coming into the service panel and also at the meter. If this doesn't correct it, check for loose circuit breakers or loose wires coming from the circuit breakers.

One common practice is to install the garbage disposal on the same circuit with the kitchen sink light - a GUARANTEED source of light dimming when the disposal is turned on. And you notice it more because it occurs simultaneous with the turning on of the disposal.

system ground rod is not the problem.

After several "experts" providing their opinions it was discovered that we had a bad breaker, but we could not see it by a visual inspection. The electrician had to remove the breaker to find the culprit. No further problems after they replaced the breaker.

I'm thinking you either have a loose neutral or the load is extremely out of balance. Also, check the neutral service conductor under load.

look around to see if you see any discolored wires. This is a sign of overload or arcing (from a loose connection).

When I was in the electrical contracting business I personally responded to many service calls. The problem you have described was among the most common that I encountered. I would start (and usually finish) my search at the wall outlets on an outside wall nearest to the service panel. The reason is that homes are often wired with the first outlet box on a circuit being used as a distribution point for the rest of the circuit. The indoor outlets on the outside walls are subjected to wide temperature variations. Add to that the fact that the full current of the circuit flows through these junctions and you have recipe for disaster. The wires become loose, having the effect of placing a load in series with the remainder of the circuit. Any sudden demand on the electrical system that would cause no noticeable effects under normal conditions will cause lights to flicker and dim.

The bigger problem, however, is that whenever you have such a condition you also have a fire hazard. Sometimes the problem will be in an outlet box on an interior wall but most will be on an outside wall. The problem usually surfaces when a house is between two and five years old. The next most likely place to find the cause of this type of problem is in the system ground. An inadequate ground can have the same symptoms.

You may have to live with a momentary dimming of the lights when a large load, on a separate circuit, kicks in. The fix might involve the electricity company running heavier service entrance cable, or adding another transformer, good luck. Adding a circuit should be the solution to the shop vac dimming the lights. Use again # 12, 20 amp breaker, and 20 amp receptacles. If you have 20 amp breakers on #14 light circuits, you might buy 15 amp breakers trading them for the 20 amp ones if you add circuits.

Tracking down loose connections is a pain. Start with pulling the cover off your breaker box. Be very careful, there is plenty of amperage to kill you. Wiggle the circuit breakers around making sure they are seated well. Keep your fingers away from the bus bars. Then using an insulated screwdriver, check the screws that hold the wires to the breakers and the neutrals to their buss. Does the box or breakers say what type they are where you can read it? If not, shut one breaker off, and pull it out. Mine say GE type TQP on the side of them them. Write it down, maybe with a marker on the door to the box. You will need that if you add circuits. Put everything back. From there, it is checking each fixture and outlet and any other junctions for bad connections.

Point an infrared thermometer at the breaker terminals, and look for a hot one.

Our eyes are very sensitive to small variations in the amount of light and the color/quality of the light. Both are affected by small variations in voltage. The high inrush of approximately 6 times the running current can make the lights 'flick, dim, blink, or dip' momentarily and this is not a code violation. When the voltage dips by 5% the light output will go down by some 10-20%; so a small momentary variation in voltage can make a large change in the light output.

One common practice is to install the garbage disposal on the same circuit with the kitchen sink light - a GUARANTEED source of light dimming when the disposal is turned on. And you notice it more because it occurs simultaneous with the turning on of the disposal.

I once had a house that had consistent low voltage, and when the electric heater was turned on, the lights almost dimmed off! The voltage went down to about 180 volts phase-to-phase (90 volts-to-ground). Seems the utility company had connected the primary phase winding but NOT to the primary neutral. There was enough current flow through the ground return to generate proper voltage as long as the lady was not making use of any heavy appliances. She had moved from a far rural area and was used to lights dimming and did not complain until the heat would not work properly. It took two line crews, two engineers, and two trips by myself to identify the missing primary neutral jumper connection at the pole.

1. Check and verify the phase-to-ground voltage to be approximately 120 volts each. If the voltage instantly dips momentarily when a large appliance is turned on (water heater, furnace, a/c, etc.) all is probably OK. Do this check at the panel, service main (line and load) and meter enclosure (line and load).

2. Turn on some 120-volt loads and check the phase-to-ground voltage. If you see any indication of the voltage going UP over 120 then you probably have a neutral problem. Do this check at the panel, service main (line and load) and meter enclosure (line and load).

Since three electricians have checked your installation, it is probably OK.

The Facts
December is the most dangerous month for electrical fires. Fire deaths are highest in winter months which call for more indoor activities and increase in lighting, heating, and appliance use. Most electrical wiring fires start in the bedroom.

The Cause
- Electrical Wiring

Most electrical fires result from problems with "fixed wiring" such as faulty electrical outlets and old wiring. Problems with cords and plugs, such as extension and appliance cords, also cause many home electrical fires.
In urban areas, faulty wiring accounts for 33% of residential electrical fires.
Many avoidable electrical fires can be traced to misuse of electric cords, such as overloading circuits, poor maintenance and running the cords under rugs or in high traffic areas.

- Home Appliances

The home appliances most often involved in electrical fires are electric stoves and ovens, dryers, central heating units, televisions, radios and record players.

Prevent Electrical Problems
Studies of electrical fires in homes show that many problems are associated with improper installation of electrical devices by do-it-yourselfers. Common errors that can lead to fires include the use of improperly rated devices such as switches or receptacles and loose connections at these devices. Both can lead to overheating and arcing that can start fires. Fires are still caused by people using the wrong size fuse or even putting a penny behind a fuse when they don't have a spare. These practices are very dangerous. The fuse is a safety device designed to limit the electricity carried by the circuit to a safe level. Electricity and water are a bad combination. All electrical devices installed outdoors should be specially designed for outdoor use. Outdoor receptacles as well as those in kitchens, bathrooms, and anywhere else near water should be the ground fault circuit interrupting type (GFCI).
Use Electrical Devices Safely
Light bulbs, especially the newer halogen types, get very hot and can ignite combustible materials that get too close. Clothing or towels should never be placed atop a lampshade and table lamps should not be used without a shade where they might fall over onto a bed or sofa. Most light fixtures are labeled to show the brightest bulb that can be safely used in that fixture; too high a wattage bulb can cause the fixture to overheat and start a fire. Extension cords are a common cause of electrical fires. You must be careful to use only extension cords that are rated for the power used by the device they are powering. Extension cords should never be used as a long term solution to the need for another receptacle. Extension cords must never be run inside walls or under rugs or furniture. Extension cords can get warm in use and must be able to dissipate this heat or they can start a fire.

Maintain Electrical Safely
The insulation on electrical cords can become damaged by wear, flexing, or age. Do not use any cord that is stiff or cracked. Some clues that you may have an electrical problem are:

Flickering lights. If the lights dim every time you turn on an appliance that circuit is overloaded or has a loose connection.
Sparks. If sparks appear when you insert or remove a plug, they could be a sign of loose connections.
Warm electrical cord. If an electrical cord is warm to the touch, the cord is underrated or defective.
Frequent blown fuses or broken circuits. A fuse or circuit breaker that keeps tripping is an important warning sign of problems.
Frequent bulb burnout. A light bulb that burns out frequently is a sign that the bulb is too high a wattage for the fixture.

Backup Power

2010-02-17T22:11:00.000-08:00

Electrical distruptions can happen at any time of the year. Some areas of Marin are subject to frequent power outages and there is never a good time to be without electricity. Some things to consider: food preparation; ability to receive news reports and updates; moving water from well pumps or sump pumps; charging cordless phones. A long outage could cause food in your fridge and freezer to thaw. Homeowners should have an emergency kit containing a flashlight, battery-operated radio, food and water, and a back-up power system readily available at all times. The picture below is an automatic transfer standby generator. We can install these for you.

When power goes out, the generator automatically kicks in. Power is not interrupted. Read about Home Generator Installation

Helping your electrician help you!

2010-02-15T22:36:00.000-08:00

Click here for troubleshooting guide.

Federal Pacific Electric (FPE) Electrical Hazards

2010-02-13T22:53:00.000-08:00

SHOULD FPE STAB-LOK^® PANELS BE REPLACED?

...Federal Pacific circuit breakers have a long and well documented history of inadequate performance. The presence of an FPE panel is a "Safety Defect" . These breakers often fail to trip when overloaded which can lead to fires. For more information search the internet for "Federal Pacific electric panel".

Most electricians or electrical inspectors can only look at the breakers ("they look OK to me"), and operate the toggle ("they click on and off OK"). But the question is: will they trip properly on electrical overload or short circuit? The history of Federal Pacific panels show them to be primary safety devices of questionable reliability. It is not correct to call non-tripping FP breakers a “fire hazard”. A fire hazard is any electrical failure that causes ignition. AS circuit breaker’s function is to stop electrical processes that could (if allowed to proceed) lead to fire in the building. If an electrical fire hazard develops in the building, the breaker is supposed to trip and minimize the possibility of ignition. If the breaker is defective, fire is more likely to result. FPE STAB-LOK circuit breakers are a danger in that regard

There is no question but that the FPE STAB-LOK^® panels should be replaced. There is no practical and safe alternative.

see another link here
and here

Personnel Protection

2010-02-11T22:58:00.000-08:00

GROUND FAULT PROTECTION

All receptacles listed below must be protected by a ground fault circuit interrupter.

a. Sheds

b. Garage receptacles that are readily accessible

c. All receptacles in an unfinished basement or crawl space at or below grade,

with these exceptions:

1. A laundry receptacle, that is not easily accessible.

2. Single receptacles not duplex type on a dedicated circuit located and

identified for specific use by a cord and plug connected appliance such as

A freezer or refrigerator.

d. Bathroom receptacles

e. All outdoor receptacles

f. Kitchen receptacles that serve counter tops

g. All temporary construction power

h. Laundry, utility and wet bar sinks. Where the receptacles are installed within 6 feet of the outside edge of the sink.

NOTE: 15 and 20 amp 125 and 250 volt receptacles in wet locations shall have in-use covers.

Aluminum Wiring in Residential Properties: Hazards & Remedies

2010-02-09T15:33:00.000-08:00

More about the Hazards of Aluminum Wire

Small 60 Electrical Services - are they adequate?

2010-02-07T16:02:00.000-08:00

60 Amp Electrical Services (photo is a thirty amp service in Tenderloin)

This service is certainly too small for today's standard! The real danger is that the exposed wires are energized. All electrical equipment with more than 50V potential must be protected in a listed enclosure.

The size of an electrical service can play a crucial role in your home.

Click here: is bigger really better?

Uninterruptible Power Supply Mainframe Computer

2010-02-05T16:14:00.000-08:00

The transfer switch on the right lets you "float" the mainframes off of the battery [which is being charged]; run the load just from the utility; or just turn the whole thing off!

Grounding! Click to see why.

2010-02-03T16:18:00.000-08:00

Click the drawing to see the the electrocution hazard. If the toaster is grounded the circuit breaker would trip. If there is only a two prong outlet on the appliance then the GFI protection required by code would protect the user.

I get shocked when touching two things at once but not either alone; which one is bad?

==> I'll be right over!

Without a tester, the only way to tell would be to touch a third or fourth thing from each, at some risk to your health.

We get shocked off faucets or pipes sometimes; what can we do? High voltage wires overhead can induce voltage in pipes/wires below, but that is usually out on the ranch, the stories abound. Otherwise, the particular circuit responsible can be identified and the stray wire located. Plus the grounding of those pipes should be checked and insured.

Theater...

2010-02-01T16:22:00.000-08:00

Report of no dimmer operation for theatre lights

Troubleshooting

Theatre manager can't believe it

remove bad relay

Rebuild and reinstall

Variable Frequency Drive

2010-01-31T16:25:00.000-08:00

New booster pump (2000 gal/min) system

2010-01-29T16:30:00.000-08:00

New pump and switch

Melted 200 Amp Circuit Breaker

2010-01-27T16:32:00.000-08:00

There was a report that half the electrical in the house was not working: no swim pool pump; dryer; half the lights not working; etc.... Turns out that the original main breaker was not installed tightly and there was arcing at one of the poles that melted right thru. We managed to fix this by the next day...

Guidelines for wiring homes

2010-01-25T16:33:00.000-08:00

Basic rules for residential wiring...

Kitchens Lighting Opportunities

2010-01-23T16:36:00.000-08:00

With all the task lighting in kitchens, a general background light may not be needed. For example, well placed recessed lights over the counters may provide ample general light. On the other hand, fluorescent lights mounted under the cabinets may leave the kitchen in need of more general light. If installed, the general light should use a fluorescent lamp and have a separate switch. It could be a surface-mounted fixture, a "cove" light mounted on top of the cabinets or a luminous ceiling.
Lighting Controls

Imagine that you had only one light switch for the whole house. That would force you to use too much light in the wrong places. Good lighting controls allow you to put the right amount of light in the right places.

Local Codes, Inspectors and California Title 24 Energy Code compliance mandate certain features.

Accent Lighting

2010-01-21T16:38:00.000-08:00

For lighting objects on a wall, the wall itself, or any vertical surface, position the track and the fixtures as shown at right.

Generally, fixtures should be aimed at a 30 degree angle from the vertical to prevent light from shining in anyone's eyes and to avoid disturbing reflections on the surface of the object. Usually, one fixture is required for each object being accented.
Measure the distance ("B" to "C") from wall, on ceiling as shown in the table below.

Mount track at "Location" ("A" to "B") from wall, on ceiling, as shown in the table

(Example: The distance from the ceiling to the center of the painting is 4 ft. Mount the track on the ceiling 27" away from the wall.)

A to B Location in inches	B to C Distance in feet
13" 20" 27" 34" 41"	2 feet 3 feet 4 feet 5 feet 6 feet

Q. How much does it cost to replace knob and tube wiring?

2010-01-19T16:42:00.000-08:00

When installed correctly knob and tube wiring was, in some ways, superior to current wiring practices. Unfortunately, this system is rarely intact after 80 or so years of use. Things that happen well after the original installation can cause major problems. For this reason, knob and tube will normally need to be replaced, especially if the insurance company requires it!

Basically there are two ways to replace knob and tube wiring. The first method is to waste no time trying to preserve walls or ceilings and run the wires in the fastest and shortest route. After the electrical wiring is installed and inspected, the damage needs to be repaired. The cost for this type of electrical work is lower if it's completed faster. Although you will save on electrical costs, you need to factor in the cost of repairing and repainting the walls and ceilings. Just remember there will also be a lot of inconvenience due to dust and dirt. The second method is much slower and cleaner and involves looking for ways to fish the wiring through the walls and ceilings. Because this process is so time-consuming you will pay more for the electrician's time. The up side is that you'll have little or no damage and only minor disruptions to your home.

The other question is the size of the main at the meter. Old K&T installations were typically undersized by today's standards.

Time, heat, and hungry critters stripped insulation here.

Our advice about improving the safety and reliability of knob and tube electrical wiring

Inspect the whole electrical: An expert should inspect the condition of the building electrical wiring, including the wires, connections, devices like receptacles, switches, and overcurrent protection by fuses or circuit breakers.
Replace bad circuits: Knob and tube circuits that have been modified, damaged, or covered with insulation should be replaced with a modern grounded electrical circuit.
Ground fault protection GFCI circuit protection and possibly arc fault protection can be added on two-wire un-grounded electrical circuits to reduce the chances of electrical shock or fire - steps that we recommend.