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Hazra Electrical Services Pvt.Ltd Director's FAQ

What is the difference between 3 phase and single-phase electricity?

Single phase:   a circuit that consists of three wires – live, neutral, and ground (earth). The main breaker in a single phase system is a single pole breaker, resembling the others in the panel, only with a higher capacity.
Three phase:   a circuit where the main breaker switches off three poles. For most home owners this is the equivalent of having 3 separate main breakers that are divided among the circuits of the home. There are 5 wires that normally constitute a three phase line, although in many homes the three phases simply supply the main and sub panels, but continue throughout most of the home as single phase lines. In most homes there are not many devices that run on three phase electricity. However, examples may include a three phase central air conditioner, a three phase oven, a 3 phase swimming pool pump, or a large 3 phase hot water boiler.

Do I need a surge protector for my computer?

Most neighborhoods in Israel still have relatively frequent power surges. Most people are well acquainted with the normal surges that cause permanent damage to appliances in a blink of an eye. But few people are aware of the smaller surges that are going on all the time. Unlike the larger surges that wreck havoc all at once, these smaller surges can slowly wear out the wiring insulation and electronic circuitry in your appliances, causing them to operate improperly and wear out prematurely. A good quality surge protector can do a lot to protect your computer as well as other appliances. I personally recommend buying a UPS for your computer. They may be slightly more expensive, but afford your computer much more protection.

What is the difference between a surge protector and a UPS?

A surge protector is a device that simply protects your computer (or any other appliance) from electrical surges, spikes, and other fluctuations in the voltage. Surge protectors vary greatly in both price and quality. It's usually wise to stay away from the "cheapy" models. They will give you very limited protection, if any.
A UPS (Uninterrupted Power Supply) usually has surge protection built in, but that's not all. It has a battery backup that offers you at least a few minutes time (if not longer), to save your work and turn off your computer (or other device) properly. Most have a communication cable between the computer and the UPS, to signal the computer when the UPS battery is low. This tells the computer to start shutting down automatically without you having to be there.
Another plus in having a UPS is that it eliminates the frequent, short blackouts or brownouts (common to many areas around Israel) which cause havoc with your hard drive. This can cause the drive to malfunction prematurely and have permanent damage.

I have many appliances with two prong plugs, and my outlets are made to accept three prong plugs. Is using 2 prong plugs in the 3 prong outlets dangerous?

Most appliances that are bought in the store with a two prong plug are either made of plastic and do not need a ground wire, or are double insulated, in which case it would actually be dangerous to have it grounded.
If the plug was installed by someone other than the factory or a reliable electrician, then it should be inspected by someone trustworthy.

What is the difference between a transformer, a converter and a power supply?

A Transformer is an electrical device by which alternating current of one voltage is changed to another voltage using coils. There are several different types, but they all basically do the same thing - change the voltage. They are usually heavy for their size due to the weight of the coils (size and weight depends on their rating).
A Converter is an electronic device that is used in some cases instead of a transformer. The converter doesn’t actually lower the voltage, but rather delays each electrical cycle making the device think it is working with the proper voltage (does not produce an output of full sine wave electricity). If you were to measure with a voltmeter the output of the converter, it would actually measure 220V (in Israel). These converters are not to be used with any electronic devices, and I personally do not recommend using them with ANY device. Although they are sold for use with hair dryers, bottle warmers, irons, etc, I’ve seen too many of these appliances ruined when used with a converter.
In actual fact, anything that supplies power is a Power Supply. But usually when people talk about power supplies, they are talking about a device that not only lowers the voltage, but also converts AC (alternating current) to DC (direct current). These are what you find on many small electronic devices (walkman, cordless telephones, desk clocks…etc), looking like a small black box that gets plugged in the receptacle, and having a cord that plugs into whatever device you're using. If you come from the US with a device using a power supply of this type rated for 110V, simply buy the 220V equivalent here in Israel. They are relatively inexpensive and work exactly like their 110V cousin. Make sure to bring the 110V power pack with you so you can be sure of buying exactly what you need.

I am told that using my air conditioner for heating costs less than using regular electric room heaters. Is this true?

Electric resistance heat (your small electric heater) works by converting electric current into heat. These heaters come in a wide variety of types and designs (baseboard heaters, radiant, convection space heaters...). All convert almost all of the electric current to usable heat and are generally considered to be 98-100 percent efficient. However, it is usually considered one of the most expensive means of heating.
Air-conditioning units use a heat pump system to heat your home. Heat pumps use electricity to move heat from one place to another. During the winter, the heat is directed inside your home while the cold air is thrown outside. The reverse is done in the summer to cool your home off. This form of heating is much more economical.
All this notwithstanding, I’m not sure that I would recommend purchasing an air conditioning unit just for the heating. In my opinion, it would take too many years to save enough in heating costs to warrant the cost of the unit itself (which can be costly). But if you intend to buy an air conditioner for the summer months anyhow, or already have one installed, by all means use it in the winter for heating and save on your heating costs.

Both the main breaker and the main ground-fault turn off everything in the house. What is the difference between them?

True, in a standard Israeli panel, both the ground-fault and the main breaker shut off everything in the home. But they both jump for completely different reasons.
A breaker basically cares how much current is going through it and it really doesn’t care what you do with it. So, for example, if you had an outlet on a 16 amp line (breaker). You can plug in a heater, toaster, hairdryer, and even stick your finger in the socket (G-d forbid), but as long as you don’t take more than what the breaker is rated for (16A in this case), it will continue to work.
The ground-fault interrupter (GFI) on the other hand, even though it’s physically built for a range of current, it really doesn’t care how much current is going though it. Whether it’s 10A, 16A, 25A, or 1000A - as long as what is going in is making a complete circuit, and nothing is escaping, the GFI is quite happy to continue working. BUT, once some current “leaks” from the line out to someplace else, the GFI will jump immediately. This is why it is sometimes referred to as “The Safety Device”. If someone would, G-d forbid, stick their finger in an outlet, part of the electricity from the line would flow through their body and on to the ground that they are standing on. The ground-fault would sense this (that not all the electricity going into the line is through the proper circuit) and jump, possibly saving his/her life.
You can have a situation where both the ground-fault and the main breaker (or specific line breaker) jump together. That would happen when a live wire shorts with something other than the neutral wire (i.e.: if the live wire of a room heater shorts with it's metal body).
To summarize, the breaker jumps when too much current is being used (including a short), and the ground-fault jumps when there is a leakage of current from the line.

Can I get electrocuted by batteries?

You sure can, but you would need a lot of batteries to accomplish this. Regular everyday batteries are safe because they have such low voltage.
You need a high enough voltage in order to get the current flowing through your body. Human skin is not a good conductor. It takes about 40 volts, or more, of electrical pressure to penetrate your skin and create an electrical current inside your body dangerous enough to harm you. Most of the batteries we use are 12 volts or less. On the other hand, if the current finds a way to penetrate the skin (through a cut or other opening), then even a 12V battery could be dangerous.

When my house was built, they did not install a doorbell. Is there an easy way to solve this?

Yes. You can install a wireless doorbell.

How can I know how many amperes my appliance uses?

The easiest way is to simply look for where it is written on the appliance. Many appliances have it marked somewhere. If not, then you can divide the watts by the volts (example: 2000 watts / 220 volts = 9.09amps). This isn’t 100% accurate because you usually have other elements that come into play, such as efficiency and a power factor. But for a "ball park" calculation it’s probably good enough.

Why do we use AC electricity instead of DC in our homes?

Power is the product of voltage x current (P = VI). For any given amount of power, a low voltage requires a higher current, thus requiring a larger size conductor (P = I2R) to transfer it from one place to another. Therefore it is more economical to transfer power using high voltage, thus requiring a smaller diameter cable.
It is very difficult to transform DC power to a high-voltage, low-current form efficiently, therefore it is not transmitted for distances greater than one mile without introducing excessive voltage drops.
On the other hand, AC power can be changed with ease using transformers to change the voltages. This makes it much more practical to use for distributing purposes. Even in your home, AC transformers can be found in use with many appliances.

Which is safer; alternating current (AC) or direct current (DC)?

Alternating current (AC) and direct current (DC) have slightly different effects on the human body, but both are dangerous above a certain voltage. The risk of injury changes according to the frequency of the AC, and it is common for DC to have an AC component (called ripple). Someone with special equipment can measure this, but the effect on a particular person is very difficult to predict as it depends upon a large number of factors. As a consequence you should always avoid contact with high-voltage electrical conductors, regardless of the type of electrical current they are carrying.

Everyone gets a 'belt' from electricity every now and then, don't they?

No, not if they are careful and follow the simple rules to securely isolate electrical equipment, and check it is dead before they start work. If you received an electric shock but were not injured then you were lucky. Next time a slight change in events may lead to a very different result. No-one is immune to injury from electricity.

How do I know if my electrical equipment is safe?

You can find out if your electrical equipment is safe by carrying out suitable checks, such as inspection and / or testing. The level of inspection and / or testing should depend upon the risks. A simple visual inspection is likely to be sufficient for equipment used in a clean, dry environment. In addition, equipment that is more likely to become damaged, or is operated in a harsh environment, is likely to require more demanding electrical tests. For further information, see: Maintaining portable and transportable electrical equipment.
Checks should be carried out often enough to ensure there is little chance the equipment will become unsafe between checks. It is good practice to make a decision on how often each piece of equipment should be checked, write this down, make sure checks are carried out accordingly and write down the results. You should change how often you carry out checks, according to the number and severity of faults found.
The best way to find out if specialised equipment is safe is to have it inspected and tested by a person with specific competence on that type of equipment. This may be the original manufacturer or their authorised service and repair agent. A reputable servicing company that deals with that type of equipment should also be competent to check its safety.

How do I know if my electrical installation is safe?

The best way to find out if your electrical installation is safe is to have it inspected and tested by a person who has the competence to do so, such as an approved contractor from:
Electrical Contractors' Association (ECA) 
National Association for Professional Inspectors and Testers (NAPIT) 
National Inspection Council for Electrical Installation Contracting (NICEIC) 
The Electrical Contractors' Association of Scotland (SELECT) 
Approved electrical contractors from these bodies will be able to advise you how to make your installation safe. These can be found in the Yellow Pages.
It is possible to do simple checks on your installation, using an electrical socket tester. This is a device that can be plugged into a socket outlet to identify if there is a wiring fault. However, be aware that many types of socket tester can't detect certain types of fault, and could indicate the socket is safe when it actually isn't.

Who should I talk to about electrical safety?

In the first instance, a competent electrical contractor should be able to give advice on electrical safety and should also be able to direct you to a suitable electrical engineer for advice about specialist areas

What voltages are dangerous?

A wide range of voltages can be dangerous for different reasons. A very low voltage (such as that produced by a single torch battery) can produce a spark powerful enough to ignite an explosive atmosphere. Batteries (such as those in motor vehicles) can also overheat or explode if they are shorted.
If a person comes into contact with a voltage above about 50 volts, they can receive a range of injuries, including those directly resulting from electrical shock (problems with breathing, heart function etc); and indirect effects resulting from loss of control (such as falling from height or coming into contact with moving machinery). The chance of being injured by an electric shock increases where it is damp or where there is a lot of metalwork.

What should I do if I think I have seen an unsafe electrical installation or equipment?

If you think you have an unsafe electrical installation you should first warn everyone to stay away from it and - if safe to do so - switch it off. You should then contact a competent person, such as an approved contractor from:
Electrical Contractors' Association (ECA) 
National Association for Professional Inspectors and Testers (NAPIT) 
National Inspection Council for Electrical Installation Contracting (NICEIC) 
The Electrical Contractors' Association of Scotland (SELECT) 
If the installation you think is unsafe is not owned by you or under your control, you should try to find out who owns it and then contact them. Electrical distribution poles, pylons and equipment should have a contact telephone number attached to them.

How do I know if someone is competent to do electrical work?

A person can demonstrate competence to perform electrical work if they have successfully completed an assessed training course, run by an accredited training organisation, that included the type of work being considered. As part of that course, this person should have demonstrated an ability to understand electrical theory and put this into practice.
A successfully completed electrical apprenticeship, with some post-apprenticeship experience, is a good way of demonstrating competence for general electrical work. More specialised work, such as maintenance of high-voltage switchgear or control system modification, is almost certainly likely to require additional training and experience.

Can I do my own electrical work?

You can do your own electrical work if you are competent to do so. Simple tasks such as wiring a plug are within the grasp of many people but more complex tasks, such as modifying an electrical installation, may not be.
It is particularly important that anyone who undertakes electrical work is able to satisfy the requirements of the Health and Safety at Work etc Act 1974 and the Electricity at Work Regulations 1989.
For work on electrical installations below 1000 volts AC, you should be able to work within the guidelines set out in BS7671 'Requirements for electrical installations. IET Wiring Regulations. Seventeenth edition'. For details, see: British Standards Institution  . Other work should be carried out according to the guidelines set out in the relevant industry standard.
Those who wish to undertake electrical testing work would normally be expected to have more knowledge and be able to demonstrate competence through the successful completion of a suitable training course.
More complex electrical tasks, such as motor repair or maintenance of radio frequency heating equipment, should only be carried out by someone who has been trained to do them.

When should I report an electrical accident to Authority?

You should report any work-related accident that comes under the requirements of the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RIDDOR) 1995.
In general, an electrical accident is reportable in any of the following circumstances:
the person dies as a result of their injuries
the person suffers a major injury
as a result of their injury, the person is away from work for more than three days, or can't undertake their full range of normal duties for more than three days
a person receives an electric shock or burn that results in loss of consciousness, the need for resuscitation or admission to hospital for more than 24 hours
plant or equipment comes into contact with overhead power lines
there is an electrical short circuit or overload that causes a fire or explosion
What should I do if I think someone is working unsafely?

If you think someone is working unsafely, you should ask them to stop immediately and tell a manager. If you are still believe they are working unsafely, you should notify Authority

When is it safe to work on live electrical equipment?

It is never absolutely safe to work on live electrical equipment. There are few circumstances where it is necessary to work live, and this must only be done after it has been determined that it is unreasonable for the work to be done dead. Even if working live can be justified, many precautions are needed to make sure that the risk is reduced 'so far as is reasonably practicable'.

How do I make my electrical equipment safe to work on?

You can be reasonably sure that your electrical equipment is safe to work on if all sources of energy (electrical, mechanical, gas, pneumatic, hydraulic, pressure etc) have been securely isolated and any stored energy has been released from the equipment. You should always follow the procedure, as set down in the instructions provided by the equipment manufacturer, and any local safety rules. If you can't find the instructions, contact the manufacturer and get them to send you instructions before you start work.
Equipment containing dangerous chemicals or other substances may have to be decontaminated before it is safe to work on. You should ask a competent person what to do in these instances. Further information on chemicals and substances is available in HSE's COSHH pages.
It is important to ensure that there is no chance a source of energy can be deliberately or inadvertently reconnected to the equipment while being worked on. This can be achieved by applying a lock to each isolation device. The person doing the maintenance should have all the keys to these locks in their possession. Warning notices should be posted at the points of isolation.
If work is to be carried out on or near exposed conductors, the conductors should be proven dead, using appropriate test equipment, before work commences.

Who has the responsibility to make sure everyone works safely?

It is the responsibility of everyone to make sure that work is safely undertaken. Managers have a responsibility to provide the resources, instruction and training necessary to enable their workers to work safely and in a manner that does not endanger others. Workers have a responsibility to make sure they keep themselves and others safe.

How often should I test my electrical equipment?

Electrical equipment should be visually checked to spot early signs of damage or deterioration. Equipment should be more thoroughly tested by a competent person often enough that there is little chance the equipment will become dangerous between tests. Equipment used in a harsh environment should be tested more frequently than equipment that is less likely to become damaged or unsafe.
It is good practice to make a decision on how often each piece of equipment should be checked, write this down, make sure checks are carried out accordingly and write down the results. You should change how often you carry out checks, according to the number and severity of faults found.

How often should I get my electrical installation tested?

Electrical installations should be tested often enough that there is little chance of deterioration leading to danger. Any part of an installation that has become obviously defective between tests should be de-energised until the fault can be fixed.
You should have your electrical installation inspected and tested by a person who has the competence to do so, such as an approved contractor from:
Electrical Contractors' Association (ECA) 
National Association for Professional Inspectors and Testers (NAPIT) 
National Inspection Council for Electrical Installation Contracting (NICEIC) 
The Electrical Contractors' Association of Scotland (SELECT) 
Approved electrical contractors from these bodies can be found in the Yellow Pages.
It is possible to do simple checks on your installation using an electrical socket tester. This is a device that can be plugged into a socket outlet to identify if there is a wiring fault. However, please be aware that many types of socket tester cannot detect certain types of fault, and could indicate the socket is safe when it actually isn't.