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Got technical electricity questions?

 

Got problems with your hot water, appliances, your meter - anything technical you're puzzled about.

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Below are some questions that have been asked previously.

Q: Is it advisable to turn off my water heater when I am away each day and turn it back on when I am back at night as a cost saving measure?
A: If you are away for 5 days or less, leave your hot water cylinder on. But if you are away for more than 5 days, then turn it off. As a general rule, hot water cost is related to how much hot water you use not how often power is available to heat it. Click here to view our Power Savings page.

Q: What is the standard voltage in New Zealand?
A: Standard New Zealand single phase voltage is 230v 50hz AND Standard New Zealand three phase voltage is 400v 50hz. The allowable variation of these supplies is +/- 6%.

Q: An electrical supplier has to deliver 230Volts with a given tolerance of plus or minus. Could you please tell me what this tolerance is? If that tolerance is exceeded it will play havoc with the surge protector and subsequently with the electronic gear it suppose to protect.
What can the customer do to protect himself in this situation?

A: The standard single phase connection is 230 volts +/- 6%. The network has a requirement to supply within this range. If a customer has a voltage problem, TrustPower can arrange for the network company to carry out a voltage investigation. We would also advise of a possible cost for this investigation if the network supply has no problems. This could mean an internal fault and therefore not the networks responsibility.

Sometimes it is only the quality of the surge protector. Quality surge protectors will drop out outside these levels. A customer can invest in a quality surge protector. New Zealand appliances are designed to work within the above voltage levels. Some appliances manufactured outside NZ are not and will fail with a small voltage difference.

Q: I have recently bought a house, but it has no heating installed. Can you please point me in the right direction to find out about night-store heating and the economics of running these heaters instead of gas or wood burners.
A: Night store heating utilizes a cheaper rate of power by operating between 11pm and 7am. The storage ability allows for heat distribution throughout the day.

The night-store requires a separate meter to be fitted to your property by an approved electrical contractor, this will allow you the benefits of a cheaper rate. If you check electrical appliance retailers in your area, they will be able to help with the additional information. You could also do a web search for night-store heating - I got some good results.

Q: Does turning a light bulb on and off use more electricity than leaving it on?
A: NO. When leaving a room for more than a few minutes turn the light off. The additional energy used in turning on an incandescent light bulb is used in the first 0.04 seconds of operation.

Q: Why does my meter still record electrical consumption when no one is at home?
A: Many appliances that we have in our homes today still consume electric power while we are away. We may not notice them using electricity, because they are silent. Here is a list of a few items your home may have that use power while you're away: aquariums, dehumidifiers, cordless phones, answering machines, refrigerators, freezers, pumps, security systems, water beds, television sets and water heaters.

Q: What are power surges and how can I protect my electronic equipment?
A: A power surge is an increase in voltage (due to a lightning strike or a high voltage line falling on a low voltage line). It can damage sensitive electronic equipment like computers. Some electronic home entertainment equipment may also be vulnerable. Protecting your valuable electronic equipment and data from surges or other changes in the power supply is usually simple and low cost. Power conditioners and/or surge protectors may help reduce voltage fluctuations and can be purchased from electrical appliance outlets. Insurance cover for fluctuating power is also an option. TrustPower can be contacted 24 hours a day 7 days a week by calling 0800 87 87 87 and you can click here to download our very handy 'Faults Fact Sheet'

Q: What causes power outages?
A: Periodically, scheduled interruptions are required to perform maintenance on our system or to your meter. These infrequent interruptions are intended to be of short duration. If an outage is planned for your area you will be notified. Unplanned interruptions are usually a direct result of storm damage, vehicle accidents, animals, or other unexpected events. TrustPower can be contacted for faults 24 hours a day 7 days by calling 0800 87 87 87 and you can click here to download our very handy 'Faults Fact Sheet'.

Q: Who is responsible for trees near power lines?
A: It is the responsibility of tree owners to ensure trees and branches are kept clear from power
lines. If you have concerns that a tree of yours, or a tree not belonging to you, may be too close to power lines, please feel free to phone TrustPower for advice on how to get this looked at. Click here for new Tree Regulations.

Q: Why does my hot water sometimes run cold?
A: This happens when the hot water is used faster than it is heated. This can occur for two reasons. Firstly, it can occur because the storage capacity is too small - solutions are to put in a bigger storage cylinder or an instantaneous heater. Secondly, it can occur because of reduced supply during system peak loadings. To reduce electricity costs, retailers offer "off-peak" supply. This supply does not operate for approximately 150 hours per year. Usually it is available for a minimum of 16 hours per day, but severe cold weather or other system emergencies can result in less supply.

Q: What is a kilowatt-hour?
A: It's the unit of electricity that your meter measures and for which we bill you each month. A kilowatt-hour (kWh) is 1,000 watts of electricity used in one hour.
For example, if a 100 watt light bulb is on for ten hours that's:
10 hours x 100 watts = 1kWh.

Q: What are line charges?

A: TrustPower bills you line charges on behalf of your local lines company. This avoids the need for you to make two separate payments. The line charges cover the cost of transporting electricity from where it is generated through the network to your home; ongoing upgrades of the network; and for regular maintenance. Line charges are made up of two components - fixed and variable. The fixed charge represents the cost of being connected to the network and the variable charge is based on your electricity consumption.

Q: Are there any benefits to using circuit breakers instead of fuses?
A: YES - The main difference between circuit breakers and fuses is that circuit breakers can be reset while fuses operate only once and then must be replaced. If your breakers or fuses trip repeatedly, call an electrician because you may have a problem with your electrical system.

Popular answers to 'Ask Sam' technical questions will be posted on the 'Ask Sam' page