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Archive for February, 2010

Knob and Tube Wiring

Sunday, February 28th, 2010

Knob-and-tube (K&T) wiring was an early standardized method of electrical wiring in buildings, in common use in North America from about 1880 to the 1940s. The system is considered obsolete and can be a safety hazard.

Home inspectors should always report knob-and-tube wiring during their inspections as a safety hazard, and advise replacement.

Facts About Knob-and-Tube Wiring:

It is not inherently dangerous. The dangers from this system arise from its age, improper modifications, and situations where building insulation envelops the wires.
It has no ground wire and thus cannot service any three-pronged appliances.
While it is considered obsolete, there is no code that requires its complete removal.
It is treated differently in different jurisdictions. In some areas, it must be removed at all accessible locations, while others merely require that it not be installed in new construction. Inspectors should be sure to know the codes in the jurisdictions in which they operate.
It is not permitted in any new construction.

How Knob-and-Tube Wiring Works:

K&T wiring consists of insulated copper conductors passing through lumber framing drill-holes via protective porcelain insulating tubes. They are supported along their length by nailed-down porcelain knobs. Where wires enter a wiring device, such as a lamp or switch, or were pulled into a wall, they are protected by flexible cloth or rubber insulation called “loom.”

Advantages of Knob-and-Tube Wiring:

K&T wiring has a higher ampacity than wiring systems of the same gauge. The reason for this is that the hot and neutral wires are separated from one another, usually by 4 to 6 inches, which allows the wires to readily dissipate heat into free air.
K&T wires are less likely than Romex cables to be punctured by nails because K&T wires are held away from the framing.
The porcelain components have an almost unlimited lifespan.
The original installation of knob-and-tube wiring is often superior to that of modern Romex wiring. K&T wiring installation requires more skill to install than Romex and, for this reason, unskilled people rarely ever installed it.

Problems Associated with K&T Wiring:

Unsafe modifications are far more common with K&T wiring than they are with Romex and other modern wiring systems. Part of the reason for this is that K&T is so old that more opportunity has existed for improper modifications.
The insulation that envelopes the wiring is a fire hazard.
It tends to stretch and sag over time.
It lacks a grounding conductor. Grounding conductors reduce the chance of electrical fire and damage to sensitive equipment.
In older systems, wiring is insulated with varnish and fiber materials that are susceptible to deterioration.

Compared with modern wiring insulation, K&T wiring is less resistant to damage. K&T wiring insulated with cambric and asbestos is not rated for moisture exposure. Older systems contained insulation with additives that may oxidize copper wire. Bending the wires may cause insulation to crack and peel away.

K&T wiring is often spliced with modern wiring incorrectly by amateurs. This is perhaps due to the ease by which K&T wiring is accessed.

Building Insulation:

K&T wiring is designed to dissipate heat into free air, and insulation will disturb this process. Insulation around K&T wires will cause heat to build up, and this creates a fire hazard. The 2008 National Electrical Code (NEC) requires that this wiring system not be covered by insulation. Specifically, it states that this wiring system should not be in…

hollow spaces of walls, ceilings and attics where such spaces are insulated by loose, rolled or foamed-in-place insulating material that envelops the conductors.

Local jurisdictions may or may not adopt the NEC’s requirement. The California Electrical Code, for instance, allows insulation to be in contact with knob-and-tube wiring, provided that certain conditions are met, such as, but not limited to, the following:

A licensed electrical contractor must certify that the system is safe.
The certification must be filed with the local building department.
Accessible areas where insulation covers the wiring must be posted with a warning sign. In some areas, this sign must be in Spanish and English.
The insulation must be non-combustible and non-conductive.
Normal requirements for insulation must be met.

Modifications:

When K&T wiring was first introduced, common household electrical appliances were limited to little more than toasters, tea kettles, coffee percolators and

clothes irons. The electrical requirements of mid- to late-20^th century homes

could not have been foreseen during the late 18^th century, a time during which electricity, to many, was seen as a passing fad. Existing K&T systems are notorious for modifications made in an attempt to match the increasing amperage loads required by televisions, refrigerators, and a plethora of other electric appliances. Many of these attempts were made by insufficiently trained handymen, rather than experienced electricians, whose work made the wiring system vulnerable to overloading.

Many homeowners adapted to the inadequate amperage of K&T wiring by installing fuses with resistances that were too high for the wiring. The result of this modification is that the fuses would not blow as often and the wiring would suffer heat damage due to excessive amperage loads.
It is not uncommon for inspectors to find connections wrapped with masking tape or Scotch tape instead of electrical tape.

K&T Wiring and Insurance:

Many insurance companies refuse to insure houses that have knob-and-tube wiring due to the risk of fire. Exceptions are sometimes made for houses where an electrical contractor has deemed the system to be safe.

Advice for those with K&T wiring:

Have the system evaluated by a qualified electrician. Only an expert can confirm that the system was installed and modified correctly.
Do not run an excessive amount of appliances in the home, as this can cause a fire.
Where the wiring is brittle or cracked, it should be replaced. Proper maintenance is crucial.
K&T wiring should not be used in kitchens, bathrooms, laundry rooms or outdoors. Wiring must be grounded in order to be used safely in these locations.
Rewiring a house can take weeks and cost thousands of dollars, but unsafe wiring can cause fires, complicate estate transactions, and make insurers skittish.
Homeowners should carefully consider their options before deciding whether to rewire their house.
The homeowner or an electrician should carefully remove any insulation that is found surrounding K&T wires.
Prospective home buyers should get an estimate of the cost of replacing K&T wiring. They can use this amount to negotiate a cheaper price for the house.

In summary, knob-and-tube wiring is likely to be a safety hazard due to improper modifications and the addition of building insulation. Home buyers need to be wary of this old system and be prepared to replace it.

Philippe Heller is the President of The San Diego Real Estate Inspection Co.

Tags: Knob and Tube
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Burglar Resistant Homes

Sunday, February 21st, 2010

Burglar-Resistant Homes

There are a number of measures that homeowners can take to ensure that their homes are not attractive to burglars. If clients are concerned about break-ins, inspectors can pass on to them basic strategies for burglar-proofing their homes.

Some interesting statistics concerning break-ins in the United States:

InterNACHI estimates that theft makes up more than three-quarters of all reported crime.

In 2005, law enforcement agencies reported more than 2 million burglary offenses.

According to a survey, burglars enter homes through the following locations:

81 percent enter through the first floor;

34 percent of burglars enter through the front door;

23 percent enter through a first-floor window;

22 percent enter through the back door

9 percent enter through the garage;

4 percent enter through the basement;

4 percent enter through an unlocked entrance;

2 percent enter through a storage area; and

2 percent enter anywhere on the second floor.

Exterior Doors:

Doors should be made of steel or solid-core wood construction. Hollow-core wood doors are more easily broken than heavy, solid-core doors.
Doors should be free of signs of rot, cracks and warping.
Doors should be protected by quality deadbolt locks. Chain locks are not adequate substitutes for deadbolt locks, although chain locks may be used as additional protection.
If a mail slot is present, it should be equipped with a cage or box. Mailslots that are not equipped with cages or boxes have been used by burglers to enter homes. Burglars can insert a contraption made of wire and cord into the mail slot and use it to open the lock from the inside, if no box or cage is present.
If a door is equipped with glass panes, they should be installed far from the lock. Otherwise, burglars can smash the glass and reach through the door to unlock the door.
Spare keys should not be hidden in obvious locations. Burglars are very good at finding keys that homeowners believe are cleverly hidden. The best place for a spare key is in the house of a trusted neighbor. If keys must be hidden near the door, they should not be placed in obvious locations, such as under a doormat, rock or planter.
A peephole can be installed in doors so homeowners can see who is on their doorstep before they open the door.
Clients should consider installing bump-resistant locks on their doors. “Bumping” is a technique developed recently that can open almost any standard lock with less effort than is required by lock-picking. This technique uses “bump keys,” which are normal keys with slight modifications. Lock companies such as Schlage Primus and Medeco manufacture a number of locks that offer some bump-resistance.

Pet Doors:

Pet doors can be used by burglars to enter homes. Some burglars have reached through pet doors in order to unlock the door. It is advisable to not have a pet door, but if one is necessary, it should be as small as possible and installed far from the lock.
A crafty burglar may convince or coerce a small child to crawl through a pet door and unlock the door. Also, some burglars are children.
Electronic pet doors are available that open only when the pet, equipped with a signaling device in their collar, approaches the door. These doors are designed to keep stray animals out of the home, and may provide protection against burglars, as well.

Sliding Glass Doors:

They should be equipped with locks on their tops and bottoms.
They should not be able to be lifted from their frames.
A cut-off broom handle, or a similar device, can be laid into the door track to prevent it from being opened.

Illumination:

Lights should be installed on the exterior of all four sides of the house. Burglars prefer darkness so they cannot be seen by neighbors or passersby.
When building occupants are not home, a few lights should be left on.
It is helpful to install exterior lights that are activated by motion sensors. Burglars that are suddenly illuminated may flee.

Windows:

All windows should be composed of strong glass, such as laminated glass, and be in good operating order.
They can be installed with bars, grilles, grates or heavy-duty wire screening. Barred windows must be equipped with a quick-release mechanism so occupants can quickly escape during a fire.
Windows should not be hidden by landscaping or structures. If landscaping or structures cannot be moved, lighting can be installed around the windows.

Landscape and Yard:

Shrubs and trees should not obscure the view of entrances. Shielded entrances can provide cover for burglars while they attempt to enter the residence.
Fences are helpful burglar deterrents, although they should not be difficult to see through.

While the house is vacant:

A loud radio can be used to make burglars think someone is home. Timers can be used to activate radios and lights to make the home seem occupied.
A car should always be parked in the driveway. A neighbor’s car can be parked there so that it appears as if someone is home.
The lawn should be cut regularly. Uncut grass is a clue that no one is home.

Other tips:

Dogs are excellent burglar deterrents. For clients who cannot own dogs, they can place “beware of dog” signs around the yard for nearly the same effect.
If no security system is installed, the client can post security alarm stickers around the yard.

In summary, there are a number of tactics that inspectors can pass on to their clients that will help safeguard their homes from break-ins. There is no substitute for a good alarm system. A quality, monitored alarm system can also contact help in the event of a fire, break-in, flood, or carbon monoxide leak even if you are not at home. For a free no obligation quote for an alarm system and monitoring, please contact us at www.sdinspections.com or info@sdinspections.com

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What is an Arc Fault Circuit Interruptor?

Sunday, February 14th, 2010

Arc Fault Circuit Interrupters

Arc Fault Circuit Interrupters (AFCIs) are special types of electrical outlets and circuit breakers designed to detect and respond to potentially dangerous electrical arcs in home branch wiring.

How do they work?

AFCIs function by monitoring the electrical waveform and promptly opening (interrupting) the circuit they serve if they detect changes in the wave pattern that are characteristic of a dangerous arc. They also must be capable of distinguishing safe, normal arcs, such as those created when a switch is turned on or a plug is pulled from a receptacle, from arcs that can cause fires. An AFCI can detect, recognize, and respond to very small changes in wave pattern.

What is an arc?

When an electric current crosses an air gap from an energized component to a grounded component, it produces a glowing plasma discharge known as an arc. For example, a bolt of lightening is a very large, powerful arc that crosses an atmospheric gap from an electrically charged cloud to the ground or another cloud. Just as lightning can cause fires, arcs produced by domestic wiring are capable of producing high levels of heat that can ignite their surroundings and lead to structure fires.

According to statistics from the National Fire Protection Agency for the year 2005, electrical fires damaged approximately 20,900 homes, killed 500 people, and cost $862 million in property damage. Although short-circuits and overloads account for many of these fires, arcs are responsible for the majority and are undetectable by traditional (non-AFCI) circuit breakers.

Where are arcs likely to form?

Arcs can form where wires are improperly installed or when insulation becomes damaged. In older homes, wire insulation tends to crystallize as it ages, becoming brittle and prone to cracking and chipping. Damaged insulation exposes the current-carrying wire to its surroundings, increasing the chances that an arc may occur.

Situations in which arcs may be created:

electrical cords damaged by vacuum cleaners or trapped beneath furniture or doors.
damage to wire insulation from nails or screws driven through walls.
appliance cords damaged by heat, natural aging, kinking, impact or over-extension.
spillage of liquid.
loose connections in outlets, switches and light fixtures.
Rodents chewing on wire insulation
Cords pinched behind furninture or in doorways

Where are AFCIs required?

Locations in which AFCIs are required depend on the building codes adopted by their jurisdiction. Inspectors are responsible for knowing what building codes are used in the areas in which they inspect.

The 2006 International Residential Code (IRC) requires that AFCIs be installed within bedrooms in the following manner:

E3802.12 Arc-Fault Protection of Bedroom Outlets. All branch circuits that supply120-volt, single-phase, 15- and 20-amp outlets installed in bedrooms shall be protected by a combination-type or branch/feeder-type arc-fault circuit interrupter installed to provide protection of the entire branch circuit.

Exception: The location of the arc-fault circuit interrupter shall be permitted to be at other than the origination of the branch circuit, provided that:

The arc-fault circuit interrupter is installed within 6 feet of the branch circuit overcurrent device as measured along the branch circuit conductors, and

The circuit conductors between the branch circuit overcurrent device and the arc-fault circuit interrupter are installed in a metal raceway or a cable with metallic sheath.

The National Electrical Code (NEC) offers the following guidelines concerning AFCI placement within bedrooms:

Dwelling Units. All 120-volt, single phase, 15- and 20-ampere branch circuits supplying outlets installed in dwelling unit in family rooms, dining rooms, living rooms, parlors, libraries, dens, sun rooms, recreation rooms, closets, hallways, or similar rooms or areas shall be protected by a listed arc-fault circuit interrupter, combination-type installed to provide protection of the branch circuit.

Home inspectors should refrain from quoting exact code in their reports. A plaintiff’s attorney might suggest that code quotation means that the inspector was performing a code inspection and is therefore responsible for identifying all code violations in the home. Some jurisdictions do not yet require their implementation in locations where they can be helpful.

What types of AFCIs are available?

The four most common types of AFCIs are as follows:

Branch/feeder—installed at the main electrical panel or sub-panel.
Outlet circuit—installed in a branch-circuit outlet.
Combination—complies with the requirements of both the branch/feeder and the outlet circuit AFCIs.
Cord—a plug-in device connected to the receptacle outlet.

Nuisance Tripping

An AFCI might activate in situations that are not dangerous and create needless power shortages. This can be particularly annoying when an AFCI stalls power to a freezer or refrigerator, allowing its contents to spoil. There are a few procedures an electrical contractor can perform in order to reduce potential “nuisance tripping,” such as:

Check that the load power wire, panel neutral wire and load neutral wire are properly connected.
Check wiring to ensure that there are no shared neutral connections.
Check the junction box and fixture connections to ensure that the neutral conductor contacts a grounded conductor.

Arc Faults vs. Ground Faults

It is important to distinguish AFCI devices from Ground Fault Circuit Interrupter (GFCI) devices. GFCIs detect ground faults, which occur when current leaks from a hot (ungrounded) conductor to a grounded object as a result of a short-circuit. This situation can be hazardous when a person unintentionally becomes the current’s path to the ground. GFCIs function by constantly monitoring the current flow between hot and neutral (grounding) conductors, and activate when they sense a difference of 5 milliamps or more. Thus, GFCIs are intended to prevent personal injury due to electric shock, while AFCIs prevent personal injury and property damage due to structure fires.

In summary, AFCIs are designed to detect small arcs of electricity before they have a chance to lead to a structure fire.

Tags: AFCI
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Reduce Fires in Your Garage

Sunday, February 7th, 2010

The purpose of this article is twofold. First, at The San Diego Real Estate Inspection Company, we’d like you to take measures to keep your garage free from fire. Fortunately, there are ways this can be done, some of which are described below. Secondly, garage fires do happen, and we’d like you to make sure that a fire cannot not easily spread to the rest of your house. While you can perform many of the recommendations in this article yourself, it is a good idea to hire an inspector to make sure your home is safe from a garage fire.

Why do many garages pose a fire hazard?

Where are you most likely to do any welding, or any work on your car? These activities require working with all sorts of flammable materials.
Water heaters and boilers are usually stored in garages, and they can create sparks that may ignite fumes or fluids. Car batteries, too, will spark under certain conditions.
Oil and gasoline can drip from cars. These fluids may collect unnoticed and eventually ignite, given the proper conditions.
Flammable liquids, such as gasoline, motor oil and paint are commonly stored in garages. Some other examples are brake fluid, varnish, paint thinner and lighter fluid.

The following tips can help prevent garage fires and their spread:

If the garage allows access to the attic, make sure a hatch covers this access.
The walls and ceiling should be fire-rated. Unfortunately, it will be difficult for untrained homeowners to tell if their walls are Type X fire-rated gypsum. An InterNACHI inspector can examine the walls and ceiling to make sure they are adequate fire barriers.
The floor should be clear of clutter. Loose papers, matches, oily rags, and other potentially flammable items are extremely dangerous if they are strewn about the garage floor.
Use light bulbs with the proper wattage, and do not overload electrical outlets.
Tape down all cords and wires so they are not twisted or accidentally yanked.
If you install recessed lights, you may have to install a fire break above them.
Don’t use extension cords as permanent wiring.

If there is a door that connects the garage to the living area, consider the following:

Do not install a pet door in the door! Flames can more easily spread into the living area through a pet door, especially if it’s made of plastic.
Does the door have a window? An inspector can inspect the window to tell if it’s fire-rated.
The door should be self-closing. While it may be inconvenient, especially while carrying groceries into the house from the car, doors should be self-closing. You never know when a fire will happen, and it would be unfortunate to accidentally leave the door open while a fire is starting in the garage.
Check the joints and open spaces around the door. Are they tightly sealed? Any openings at all can allow dangerous fumes, such as carbon monoxide or gasoline vapor, to enter the living area. An inspector can recommend ways to seal the door so that fumes cannot enter the living area.

Concerning items placed on the floor, you should check for the following:

Store your flammable liquids in clearly labeled, self-closing containers, and only in small amounts. Keep them away from heaters, appliances, pilot lights and other sources of heat or flame.
Never store propane tanks indoors. If they catch fire, they can explode. Propane tanks are sturdy enough to be stored outdoors.

In summary, there are plenty of things that you can do to prevent garage fires from spreading to the rest of the house, or to keep them from starting in the first place. Also, be sure your smoke detectors are operational. Test them at least twice a year. They could save your life.

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QR Codes

Friday, February 5th, 2010

QR codes. What they are, and how they can help sell houses

This is an older article we posted, but it is very useful for real estate agents. If you are one of those agents interested in the latest technology to market yourself, QR codes could give you an advantage over other agents in your area. QR codes are cell phone readable bar codes that can store URL’s, contact info, phone numbers, etc. “QR” stands for

Scan this QR code to see our video on your smartphone.

Quick Results. They are a simple way to link offline printed material to online content with the least effort. The funny looking image is a smartphone readable link to web content. In other words, just like a barcode is translated by computer to a number, QR codes have a website embedded into the image. Instead of typing in a long website address, the image can be scanned in an instant and the user directed right to your content on the internet.

Imagine a potential buyer out gathering flyers on a Sunday afternoon. They see a QR code on your flyer or sign and scan it with their free QR reader app. It takes them straight to your virtual tour where you end with an invitation to show them the house – all while they are standing in the driveway!

Go to your phone right now and find a QR code reader, then scan the code above. (There are stand-alone apps that read QR codes. There is also a QR code reader built into the free Starbucks(r) app.) The code at right will link you to our TV commercial. Just start the app, then point your smartphone camera at the QR code on the screen.

Think of all the places these can be used; post cards, flyers, business cards, and yard signs. Put it on your business cards to link your Facebook page. There are even a companies that will print shirts and temporary tattoos!

QR Code on Flyer
Here is a link to a simple QR Code ganerator that you can use for free. It generates an image which you can save to your computer. You can use QR Codes to embed nearly any information such as a URL, contact info, email address, etc. Be sure to test the image before printing thousands of flyers. You should include a link or web address of a reader for your clients so they can easily find one.

QR-Code Generator by Mobile-Barcodes.com

History of the QR Code

QR-Codes first hit mainstream when they were initially used for tracking parts by vehicle manufacturers. After a while, companies began to see the scope for where QR-Codes could be used elsewhere within the world. The most commercial use for QR-Codes is in the telecommunications industry where the mobile phone seems to be the biggest driver of their popularity.

The codes have been around since the mid 1990’s in Japan, and then made their way to Europe. They are just starting to get used in the U.S. Advertisers use QR codes so that people can quickly scan an advertisement on a bus, a store window, or magazine ads and be taken directly to online content.

QR-Codes are capable of handling of sorts of data, including numbers, alphabetic characters, Kanji, Kana, Hiragana, symbols, binary, and control codes.

A total of 7,089 characters can be encoded in one symbol alone.

QR-Code Data Capacities
Numeric only	Max 7,089 characters
Alphanumeric	Max 4,296 characters
Binary (8 bits)	Max 2,953 bytes
Kanji, full-width Kana	Max 1,817 characters

So next time you see one of these codes you’ll know what they are. You’ll see them all over magazine ads, in store windows, and even on buses and billboards. Please feel free to pass this on to your colleagues or re-post.

About the author: Philippe Heller is the President of The San Diego Real Estate Inspection Company, one of the largest private home inspection companies in San Diego. The company uses state-of-the-art testing equipment and is a leader in the industry. Be sure to subscribe to the blog on the site, or “like” their Facebook Page.

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