December 13, 2005
December Issue: Electrical Wiring
©2005
Hi,
Welcome to the December issue of The HomeTeamKC Report. This report provides REALTORS® and Homeowners with helpful information about residential homes from a home inspector's perspective.
I receive a lot of questions concerning safety related to electrical wiring. These questions are a concern since, according to the Consumer Product Safety Commission, problems in home wiring are associated with more than 40,000 home fires each year. These fires claim over 350 lives and injure 1,400 victims annually.
With that in mind, we are devoting this issue of The HomeTeamKC Report to electrical wiring in the home and related safety issues. Some good information for you and your clients with lots of illustrations! Hope you enjoy it.
One other item you and your clients are going to enjoy: there will not be any pricing increases for our services this coming year. Our current price list will remain unchanged as we enter into the new year!
Thanks for your interest and call or email us anytime with any questions you may have.
Mike
The HomeTeamKC
P.S. If you have problems viewing this newsletter in your email browser, click this link to view this and past newsletters from our archives.
The archives are becoming a treasure trove of good information about homes. Be sure to pay a visit now and again: you are sure to find something of interest. Archives
What you’ll find in this issue of
the HomeTeamKC Report:
KNOW YOUR ELECTRICITY
·Knob and Tube Wiring
·Ground Fault Circuit Interrupters (GFCI's)
·Concerns with Aluminum Wiring
·What about Receptacles?
·A Wiring Primer
·Inspecting Household Wiring
·Outdated Equipment
·A Summary of the History of Electrical Wiring
PRICING
·Quick Access to Our Current Pricing Sheet
KNOW YOUR ELECTRICITY
We all enjoy the convenience of electricity in our homes, but some times we take the safety of our electricity for granted. Electricity in homes has only been around for about the last hundred years. Over the years improvements to the methods and equipment used, have been made to ensure better safety. With this in mind, you can understand that the age of a home can make a difference in the safety of the wiring system. Older wiring simply has a greater potential of causing a fire than newer wiring.
More than forty thousand home fires are caused due to wiring problems each year. A lot of these fires can be prevented by homeowner awareness, such as noticing any Unusual Behavior: unusual behavior such as blinking lights, lights getting brighter, brown outs, arcing, sparking, or that "electrical smell", is an indication of loose connections or poor splices. This causes fires and must have immediate attention from a professional.
- Knob and Tube Wiring
- Knob and Tube Connections
- The newest (original) Knob and tube wiring is around 70 years old
- It is a greater fire hazard
- It is a greater electrocution hazard
- It is obsolete to modern use standards
- More and more insurance providers are denying homeowner’s insurance on houses with knob and tube wiring
- It is an open air wire, and not designed to be covered with insulation
- In most cases the insulation is brittle and damaged (from age)
- More likely to have improper splicing Return to Table of Contents
- Ground Fault Circuit Interrupters (GFCI's)
If your home was built pre mid 1960’s, it was wired with a two-wire system. This system is referred to as an open ground system because it only has a hot wire and neutral wire. After the mid sixty’s, house whole wiring used a three wire system. This system consisted of the hot wire, the neutral wire, and a ground wire for added safety. The easy way to tell if you have an open ground system is look at the receptacles. If they will only accommodate a two-prong plug, then it is an open ground system.
To help prevent a shock hazard it is important for GFCI’s to be installed in the bathrooms, kitchens, garages, and all exterior receptacles.
- Interrupts circuit to protect equipment (not people)
- Must not exceed wire capacity or equipment load
- GFCIs are designed to reduce the chance of serious shock to people
- Three types of GFCIs are:
- Receptacle type
- Circuit Breakers
- Portable Devices
- AFCIs are designed to reduce fire hazards
- New Electrical code effective 01/01/02’ will require AFCI circuits in bedroom circuits on all new homes Return to Table of Contents
- Concerns with Aluminum Wiring
If your home was built from the mid 1960's to the early 1970's, the wiring for the wall sockets may be single stranded aluminum. This is a potential fire hazard. According to the U.S. Consumer Product Safety Commission, fires and even deaths have been reported to be caused by this hazard. Problems due to expansion can cause overheating at connections between the wire and devices (switches and outlets) or at splices.
CPSC research shows that "homes wired with aluminum wire manufactured before 1972 are 55 times more likely to have one or more connections reach "Fire Hazard Conditions" than are homes wired with copper. "Post 1972" aluminum wire is also a concern. For your safety the aluminum wiring in the home should be evaluated by a licensed electrician to determine if the hazard exists.
- What about receptacles?
In household wiring the light circuits and the receptacle circuits are wired in a configuration called “branch circuits”. What this means is that the receptacle that is the closest to the main panel gets the electricity directly from the panel. The next receptacle gets its electricity from a wire branched off of the first receptacle, then the next receptacle branched from the second receptacle, and so forth and so on.
So for an example; if you only have something plugged into the fourth receptacle away from the main panel, you are still pulling electricity through all of the other plugs in between that one and the main panel. With this in mind you can understand how important it is to replace any of the old receptacles, and not just the one you use a lot.
Receptacles go bad from age and use. What happens is the contacts inside the receptacles get weak and no longer provide a tight connection. The problem is that loose connections cause fires.
Receptacles that may need replacing are:
- Two prong receptacles
- Receptacles that hum or buzz
- Receptacles that have dark stains in the face
- Receptacles that will not hold a plug tight
- Any receptacle that is cracked or broken
- A Wiring Primer
If your home was built before the mid 1930’s it is likely that Knob and Tube wiring was used. Knob and Tube Wiring should be evaluated by a licensed electrician, and in many cases replaced.
The facts about Knob and Tube:
Understanding Interrupters
The term “interrupter” refers to fuses, breakers, GFCIs, or any other device that is designed to interrupt the electricity traveling thought a circuit. Here is a list of some of the circuit interrupts and their use.
Main Breakers
Ground Fault Circuit Interrupters (GFCI)
Remember never work on any electrical device until you are without a doubt that the power is shut off from that device.
It is important to know your skill level, and not to do any work that could cause you or your family harm. It is a good idea to have your electrical system evaluated when having other electrical work done. It does not take a qualified electrician long to evaluate the safety of your electrical system, it’s worth it!
These are some of the things that are included in the electrical portion of a home inspection:
- Check for open splicing (wires connected outside of a junction box)
- Check junction boxes for covers and open knock-outs
- Look for knob and tube wiring
- Test outlets for open grounding and reverse polarity
- Check for GFCI protected outlets in kitchens, baths, and exterior receptacles
- Check for cover plates on all receptacles
- Check to make sure that all electrical devices are securely mounted
The term “out dated equipment” is often used to describe some of the following electrical issues: Sixty amp Service Panels
- Not adequate for today's household electrical demands
- More and more Insurance providers are denying homeowners insurance on houses with less than one hundred amp service
- More likely to be a shock hazard
- With two wire systems it is even more important for GFCI’s to be installed in the suggested places
- The newest (original) Knob and tube wiring is around 70 years old
- It is a greater fire hazard
- It is a greater electrocution hazard
- It is obsolete to modern use standards
- More and more Insurance providers are denying homeowner’s insurance on houses with knob and tube wiring
- It is an open air wire, and not designed to be covered with insulation
- In most cases the insulation is brittle and damaged (from age)
- More likely to have improper splicing
Open ground wiring (Two wire wiring)
Knob and Tube Wiring
Electrical dates of interest
- 1886–First residential use of AC current (Great Barrington, MA)
- 1890-First Residential electric lights introduced
- 1897-National Electrical Code established
- 1900–early 1930’s–Knob and Tube wiring used
- 1930’s-Wide use of armored cable (BX)
- 1940’s-Increased use of non-metallic cable (two wire romex)
- Early 50’s-early 60’s-Introduction of rag romex (still two wire)
- Early 60’s NEC codes changed to the use of the three slot outlets
- 1962-1973- Single strand aluminum wiring used in 15/20 amp circuits
- 1973-GFCI’s introduced for exterior receptacles
- 1975- Code mandate for GFCI’s in bathrooms of new construction
- 1974 or75-Edison based fuses prohibited for installation unless they were equipped with type S fuses
- 1978-GFCI’s mandated for garages in new construction
- 1987-Code revised to include GFCI’s in kitchens and one in a basement
- 1990-Code revised to require GFCI’s in crawlspaces.
Hope you enjoyed our tour of the world of Electrical Wiring. See you next month!
©Illustrations from
The Illustrated Home Return to Table of Contents
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