Electrician Job Interview Preparation Guide

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Fuse:
A fuse has a wire that melts with the heat of a short circuit or high current and interrupts the circuit. Once melted, you have to replace it.

Circuit Breaker:
A circuit breaker interrupts the current without melting ( a pair of metal sheets with different thermal expansion coefficient, for example) and can be reset.

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The Electrician is a home electrical service created by The Electrician Service Co. Inc. serving homeowners, in Nassau and Suffolk Counties.

This is used to describe the size and quantity of conductors
in a cable. The first number specifies the gauge. The second
the number of current carrying conductors in the wire - but
remember there's usually an extra ground wire. "14-2" means
14 gauge, two insulated current carrying wires, plus bare ground.

-2 wire usually has a black, white and bare ground wire. Sometimes
the white is red instead for 220V circuits without neutral. In
the latter case, the sheath is usually red too.

-3 wire usually has a black, red, white and bare ground wire.
Usually carrying 220V with neutral.

Statistics show that fuse panels have a significantly higher
risk of causing a fire than breaker panels. This is usually
due to the fuse being loosely screwed in, or the contacts
corroding and heating up over time, or the wrong size fuse
being installed, or the proverbial "replace the fuse with a
penny" trick.

Since breakers are more permanently installed, and have better
connection mechanisms, the risk of fire is considerably less.

Fuses are prone to explode under extremely high overload. When
a fuse explodes, the metallic vapor cloud becomes a conducting
path. Result? From complete meltdown of the electrical panel,
melted service wiring, through fires in the electrical
distribution transformer and having your house burn down.
Breakers won't do this.

Fuses and circuit breakers are designed to interrupt the power
to a circuit when the current flow exceeds safe levels. For
example, if your toaster shorts out, a fuse or breaker should
"trip", protecting the wiring in the walls from melting. As
such, fuses and breakers are primarily intended to protect the
wiring -- UL or CSA approval supposedly indicates that the
equipment itself won't cause a fire.

Fuses contain a narrow strip of metal which is designed to melt
(safely) when the current exceeds the rated value, thereby
interrupting the power to the circuit. Fuses trip relatively
fast. Which can sometimes be a problem with motors which have
large startup current surges. For motor circuits, you can use
a "time-delay" fuse (one brand is "fusetron") which will avoid
tripping on momentary overloads. A fusetron looks like a
spring-loaded fuse. A fuse can only trip once, then it must be
replaced.

Inside the panel, connections are made to the incoming wires.
These connections are then used to supply power to selected
portions of the home. There are three different combinations:
1) one hot, one neutral, and ground: 110V circuit.
2) two hots, no neutral, and ground: 220V circuit.
3) two hots, neutral, and ground: 220V circuit + neutral,
and/or two 110V circuits with a common neutral.

In general, there is no requirement to upgrade older dwellings,
though there are some exceptions (ie: smoke detectors in some
cases). However, any new work must be done according to the
latest electrical code. Also, if you do ``major'' work, you
may be required to upgrade certain existing portions or all
of your system. Check with your local electrical inspector.

Every electrical device or component must be certified by the
Canadian Standards Association (or recognized equivalent) before
it can be sold in Canada. Implicit in this is that all wiring
must be done with CSA-approved materials. They perform testing
similar to the UL (a bit more stringent), except that CSA (or
recognized equivalent) approval is required by law.

Again, like the UL, if a fire was caused by non-CSA-approved
equipment, your insurance company may not have to pay the
claim.

Note: strictly speaking, there usually is a legal way around
the lack of a CSA sticker. In some cases (eg: Ontario), a
local hydro inspection prior to purchase, or prior to use, is
acceptable. The hydro inspector will affix a "hydro sticker"
to the unit, which is as good as CSA approval. But it costs
money - last I knew, $75 per unit inspected.

The UL stands for "Underwriters Laboratory". It used to be
an Insurance Industry organization, but now it is independent
and non-profit. It tests electrical components and equipment
for potential hazards. When something is UL-listed, that means
that the UL has tested the device, and it meets their requirements
for safety - ie: fire or shock hazard. It doesn't necessarily
mean that the device actually does what it's supposed to, just
that it probably won't kill you.

The UL does not have power of law in the U.S. -- you are
permitted to buy and install non-UL-listed devices. However,
insurance policies sometimes have clauses in them that will
limit their liability in case of a claim made in response to
the failure of a non-UL-listed device. Furthermore, in
many situations the NEC will require that a wiring component
used for a specific purpose is UL-listed for that purpose.
Indirectly, this means that certain parts of your wiring
must be UL-listed before an inspector will approve it and/or
occupancy permits issued.

The NEC is a model electrical code devised and published by the
National Fire Protection Association, an insurance industry group.
It's revised every three years. The 1993 version has been released.
You can buy a copy at a decent bookstore, or by calling them directly
at 800-344-3555. The code exists in several versions. There's the
full text, which is fairly incomprehensible. There's an abridged
edition, which has only the sections likely to apply to most houses.
And there's the NEC Handbook, which contains the ``authorized
commentary'' on the code, as well as the full text. That's the
recommended version. Unfortunately, there's no handbook for
the abridged edition. And the full handbook is expensive --
US$65 plus shipping and handling.

If you are building a new property it is helpful for the electrician to see the plans. Also discuss your personal needs so that power outlets are conveniently placed.

It’s OK to visit the hardware shop and buy the switch you like the look of. But you need a licensed electrician to complete the work. A licensed electrician will issue a certificate to show the work complies with building standards. That way your property won’t be devalued or insurance issues crop up in the event of a problem.

Whenever you have a job relating to power or wiring.

An electrical contractor can install solar panels to your property. Excess energy collected by your solar panels is fed into the electrical grid. You receive credit for power generated on your electricity bill.

Old wiring can be dangerous. Use a licensed electrician with experience in older homes or property.

Only a qualified electrical contractor is licensed to properly test your installation for safety and issue a compliance certificate.

A safety switch is a device fitted to the property supply that cuts out electricity almost instantly in the event of a significant power leak or surge.

Have an electrical contractor install a safety switch or circuit breaker. Nearly all electrical accidents involving consumer products could have been prevented by one of these devices.

Electrician is a trade qualification and electrical contractors are licensed in each state. Many electricians also choose to belong to professional associations like NECA (National Electrical & Communications Association).

Be sure to hire a licensed professional electrician. There a several reasons for this:

1. you’ll get a better job
2. work will comply with the building code
3. you won’t have an insurance problems if something goes wrong

Most good quality electricians will provide you with a detailed quotation free. For smaller jobs, a price estimate is often available over the phone.

Electrical contractors are qualified to install and connect wiring, fixtures and appliances. They also install solar panels and other equipment for generating power.

One of the best ways to save money on electrician costs is to do some research. Find out how much electrician companies and individual electricians charge for their services. Compare quotes between different electrician service providers and determine which one is best for your budget. You can learn more tips from our “Work and Costs” section.