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Transformer Troubleshooting Questions

Are junction boxes required when connecting lights to a transformer? How is a transformer connected? Knowing what transformer to use and how to install it can keep your electrical circuits safe and trouble free. The opinions of Experts will tell you what to do and how to do it. Given below are a few of the questions that Experts have answered.

Are junction boxes required for each 6 inch whip for 12 volt hockey puck lights connected to a low voltage transformer?

There is no need to use junction boxes. Open splices are approved on low voltage wiring.

What could cause a GE security system that is no longer in use to beep every minute and give a low battery warning and how can the warning be deactivated?

These systems also have a low voltage transformer that plugs into an outlet. It is normally located in the vicinity of the alarm panel or of the remote for it. It is typically a small square or rectangular shaped device. Once it is unplugged the wires from it can be cut if it is not going to be used again. Alternatively the transformer can be unplugged but left connected for use in the future.

Is it normal for a surface mount transformer (model LM-EN24-600M) for a Solorail System in a kitchen to make an intermittent buzzing sound that typically lasts for about 15 minutes?

It is not unusual for transformers to make a noise of this kind. This is generally not of any significance. Most of these devices have a small circuit breaker installed as a safety measure. The problem could be that of a simple loose connection. However, it would be advisable to have the unit checked by an electrician.

If a UB 1640W plug in wall transformer has 2 red wires and a green one connected to the middle screw, where is the other red wire (which breaks off from the first one) to be connected?

The unconnected red wire should be connected to an open terminal.

If a dryer needs to be connected to a transformer to step down voltage from 240 to 208, what does the 2013 California Electrical say about the use of hardwire and plug in connections?

The 2013 California Electrical Code, which is based on the 2011 National Electrical Code says:

  • Hardwire connections between the dryer and the transformer are not allowed. Almost all washers and dyers have plug and cord connections and these must be used, unless the manufacturer’s installation instructions specify otherwise.

  • The transformer should not have a plug in connection to the outlet. The uses of flexible cords are clearly specified and the connection between the transformer and the outlet are not covered.

What do the KVA ratings on a transformer mean?

KVA is the rating of the transformer and specifies how much load it can accept. 1 KVA = 1,000 volt amps. A volt amp is basically the same as a watt. In other words, a 50 KVA transformer can handle 50,000 watts of power. To  put this in perspective, a TV uses about 250 watts and a hairdryer about 1,000 watts or 1 kilowatt. If the hair dryer is kept on for 1 hour, the power consumption will be 1 kilowatt hour or 1 unit of electricity that will appear on the bill.

Will moving from a 100 KVA to a 50 KVA unit will save electricity and reduce the size of the electricity bill?

While it is correct that transformers do suffer from a certain amount of loss, it is mainly in the form of heat. A transformer works to step down voltage. The current used is based on the loads connected to the transformer and this is not affected by the voltage. Electrical billing is based on the loads so reducing the voltage will not have an impact on the amount of the bill.

With a rated load panel of 400 amps and 208 volts, should the transformer be rated to full capacity or at 20% less using the 80% rule?

The transformer in this case should be sized for 400 amps at 208 volts. Since there is no definitive way of knowing what loads will be on or off at any given time under normal conditions, the calculated load will be 400 amps. This means that 400 amps will require a 150 KVA 3 phase transformer which is rated for 416 amps.

Will it be more cost effective to wire a room with low voltage wire to operate LED bulbs or to install special low voltage fixtures with inbuilt transformers that will work on normal domestic wiring?

If the light fixtures are designed for 120 volts, it will be better to retain them. Running 12 volts requires big wires. To clarify, a 5 watt bulb at 12 volts uses 0.5 amps while at 120 volts the amps are 0.04. As the wattage in a circuit increases, the amperage will rise, requiring a larger wire size. Distance too has an effect. The further a circuit runs, the greater the voltage drop and in the case of 12 volts, the drop is rapid. A circuit designed for 12 volts will need wiring that can accept an electric dryer load. Using low voltage fixtures with inbuilt transformers will be the better option.

Finding the right transformer for your electrical needs and circuits is a complex task. The guidance you receive from Experts will help you to make informed decisions. Experts can be conveniently contacted online from the comfort of your home.

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