Frequently Asked Question

 


Q What is an "electrical fire"?

An electrical fire is a fire started from electrical arcs and sparks. A drape which catches fire from being too close to an electrical heater is not considered an electrical fire.

Electrical arcing and sparking usually occurs in confined spaces such as inside the wall, outlet, appliance, or the attic. Some arcing does occur in the living space from defective appliances and overheated or damaged extension cords.

Smoke detectors provide little advance notice with most electrical fires. The smoke from most electrical fires that start inside walls and attics rises and is vented to the outside via roof vents. The fire weakens the attic support structure, allowing the ceiling to collapse before the smoke detector can detect a fire. Many electrical fires result in fatalities.

Things that lead to arcing and sparking are: poor wiring connections, bad appliance or electrical cords, corrosion at connections (especially aluminum wiring), worn or deteriorated wiring insulation, old outlets, old switches and overhead lighting. When current flows through bad connections small amounts of heat is produced. In the case of overhead lighting, heat is produced any time the lights are ON. Heat deteriorates insulation on the wiring allowing the Black (hot) to White (neutral) or Black (hot) to Ground wire to short out. Large amounts of arcing and sparking is then produced.

Zlan laboratory tests show that wiring insulation can breakdown in less than 30 seconds when the white and black wires are mashed together. Even the best 105 degree-C rated wiring broke down in less than ten minutes. When wiring is installed in junction boxes, outlets, switches and overhead lighting; its length is extended for ease of installing the outlet, switch, etc... This extra wire must be folded (crammed) back into the connecting box. It is common for the wires to overlap each other in the junction box with an applied force of over 50 pounds when the screws are installed.

 

Q What is the probability of my home catching fire because of electrical problems?

1 out of 5 fires originate from electrical problems according to USFA, (United States Fire Administration via the National Fire Incident Reporting System). There is a fire every 67 seconds in the US and a fatality every 105 minutes.

Most tragic fires which start at night or in the early morning hours are electrical fires. Check with your local Fire Marshall or news reports.

Zlan's patented technology dramatically reduces the probability of an electrical fire. (see patents page).

 

Q What do you mean by "nuisance tripping"?

A nuisance circuit breaker trip occurs when it mistakes a normal operating condition for a hazardous condition, such as high motor startup currents. A 20 amp circuit breaker must withstand 100 amps of motor startup current.

Also, it is a nuisance to constantly have to reset a defective circuit breaker. However, it may not be defective, it may be a warning that the wiring and its connections are being overloaded with too much current or too many appliances.

Never try to solve the problem of a nuisance tripping circuit breaker by putting in a higher rated breaker; i.e., a 30 amp breaker in place of a 15 or 20 amp breaker. The new circuit breaker may no longer trip, appearing to have solved the problem. However, a bigger trouble has been inserted, the time to trip for a real problem has now more than doubled! And in some cases the breaker may not trip at all (see "How does wire length affect the trip time...?").

Today's circuit breaker seldom nuisance trips. This is at the expense of not being able to detect most of the conditions that lead to an electrical fire.

 

 Q What causes arcing in electrical circuits?

Arcing is due to electrical current jumping across an air gap producing heat and a visual light. Low current arcing does not always contain sparks. Some appliances contain acceptable arcing; e.g., the electric drill produces arcs when the electrical contact brushes move from commutator section to commutator section. This type arcing is not hazardous.

Wiring arcing above 5 amps can produce sufficient heat and sparks to start a fire. Today's circuit breaker can only respond to arcing above its rating, i.e. a 20 amp breaker ignores arcing below 20 amps. Today's circuit breaker treats arcing above 20 amps as overload current. But, the circuit breaker has been designed to be slow in its response to intermediate overloads. Further, today's circuit breaker technology (thermal bi-metallic strips & magnetic aids) does not permit a faster response without increasing nuisance tripping to an unacceptable level.

Sparks are the molten metal which is thrown off and have the appearance of a arc welder or 4th of July sparkler. Electrical fires start after the wiring shorts out and before today's circuit breaker can respond.

Series arcing is arcing current which is limited by the load or appliance current. If a toaster uses 12 amps of current, then an intermittent open in the wiring or connections can only cause a maximum arc of 12 amps. Hence, the arcing current is limited by the appliance current. Should arcing occur at a loose connection, all current passing through that connection makes up the arcing current; i.e. a 12 amp toaster and a 5 amp light could produce a 17 amp arc.

Today's circuit breaker seldom/never trips for series arcing. Any time a switch is turned off, breaking the current to an electrical appliance, a series arc is formed. The greater the current drawn (more watts of power required) by the appliance, the greater the arc that will be developed. Switches are designed to tolerate these arcs; however, a poor connection can easily form in a wall receptacle or appliance plug, where it now becomes an arc source generating high temperatures, which can cause the insulation on the wiring to breakdown. Frayed or broken wiring in extension cords is another source of series arcing.

Parallel arcing is arcing current limited only by the resistance of the wiring and is referred to as short circuit current. When the load/high/black wire comes into direct contact with the neutral/low/white or ground wire maximum short circuit current flows. Typical short circuit currents in a home range from 45 amps to 450 amps. About 65% of the wiring in a 2,000 square foot home ranges between 45 amps and 200 amps. An extension cord can reduce 300 amps of short circuit current at the outlet to less than 100 amps at the end of the extension cord.

It is believed that most electrical fires are started from arcing currents ranging from 30 amps to 250 amps. It should be noted that today's 20 amp circuit breakers are very slow to respond to short circuit currents below 250 amps.

 

Q Why is arcing considered a serious problem?

By its very nature arcing develops heat in a localized area and produces hot embers in the form of sparks which can then ignite dust, wiring insulation, or other combustibles that may be nearby. This heat may be in an enclosed ceiling or wall outlet box, thereby causing a fire that can go undetected by people or smoke detectors until the fire is beyond control. Also, in most cases the circuit breaker cannot see or detect arcing until it is so damaging that a massive short circuit current has developed.

 

Q Why is it difficult to protect against arcing?

Improving arcing protection in today's circuit breaker, using yesterday's technology (thermal & magnetic), would increase nuisance tripping beyond acceptability. Today's circuit breaker has three speeds of response; no response, slow response and fast response. These responses are generally grouped by the amount of load current:

No response are arcing currents at or below the circuit breaker's rating. (For a 20 amp breaker, it does not response to arcing at or below 20 amps). Most series arcing occurs in this zone. While series arcing of itself is not very dangerous, it can quickly lead to parallel arcing whose current is only limited by the wiring resistance. See Slow response.

Slow response are arcing currents ranging from 1 to 15 times the circuit breaker's rating. (For a 20 amp circuit breaker the response time is slow for arcing currents between 20 amps and 300 amps). This current range is usually associated with parallel arcing; and, most outlets and extension cords are in this short circuit group. Today's circuit breaker with yesterday's technology offers little or no protection. This is the most hazardous zone and the cause of most electrical fires.

Fast response are arcing currents above 15 times the circuit breaker's rating. (For a 20 amp circuit breaker the response time to overload current over 300 amps is considered to be fast). There are very few outlets (and in some cases, none) in homes and businesses which have a short circuit current rating of over 300 amps.

Arcing is usually the result of an intermittent connection or short circuit. The average current may therefore be low enough to greatly extend the time to trip of the circuit breaker, if the breaker trips at all. For example, even the high current parallel arc may have short duration arcs, and therefore a much lower average current, thus placing it in the "slow response" time zone.

 

Q How does wire length affect the trip time of today's circuit breaker?

When the wiring shorts out, the longer the wire the longer it takes today's circuit breaker to trip. The delay time between the occurrence of a short circuit (when the arcing and sparking begins) and the tripping of the breaker may vary from a few tenths of a second to several minutes, depending upon the available short circuit current. The variance in short circuit current is due to the type, size, and length of wire installed. In small homes the typical short circuit current, measured at the outlet, varies from 900 Amps down to less than 100 Amps (without extension cord). While in a larger home it may go as low as 30 Amps, at which level the trip time could exceed several minutes! Extension cords dramatically degrade the quality (reduce the short-circuit current) of existing outlets and extend the circuit breaker's trip time.

The longer it takes to trip the circuit breaker, when sparks start flying, the more likely that a fire will be started.

 

Q Can I do something to help reduce the chance of an electrical fire?

No, not without adding an arc detection device, such as, Zlan's DE circuit breaker. Even though presently there are a few warning signs, such as: warm outlets, flickering lights or warm extension cords, today's circuit breakers cannot detect or trip for these conditions. Often times these arcing conditions are out of sight (inside walls and attics). Both old and new homes and businesses are subject to electrical fires due to arcing.

Electricians are unable to give your wiring a clean bill of health and warrant its safety. Electricians lack proper test equipment for testing for arcing conditions. Even if test equipment was available, hazardous conditions could occur moments after inspection.

 

Q How do you pronounce Zlan?

Zlan is a two syllable word "Z'-lan" pronounced Zee’-lun or Zee'-lan. Zlan is pronounced similar to New Zealand without the "New" and "d". Note that there is no "d" at the end of Zlan.

The name Zlan is the result of two people (George Spencer & Karl Davenport) setting around a table trying out names. However, since "Z" is the last letter of the alphabet and LAN stands for Local Area Network, it could be said (as an after thought) that Zlan is the last word in communications.


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