Replacing your transfer switch – what does it mean?



A condominium has a large number of critical and complex systems that need to work together in order to ensure a safe and comfortable environment. A transfer switch is one of them – but what is it and how do you go about replacing it if it breaks? We, here at the Electric Blog, thought we would shed some light on the subject to ensure property managers and residents alike are better prepared for the inevitable

What exactly is a transfer switch?
These days, most condominiums have a back-up generator in place to provide power in the event of a black-out. The transfer switch is the key piece of equipment that connects the generator to the building’s power system. It is this vital component that monitors the utility power. If there is an interruption in the power, the transfer switch will be able to detect it and start the generator. Once the generator is fully running, the transfer switch will then open the utility line and connect to the generator’s power. As soon as the utility power is restored, the sequence is reversed and the generator will turn-off after a cool down period.

Why would I replace my transfer switch?
The majority of switchgear is fairly mechanical and static, but the transfer switch is different. These switches have sensitive electronic circuit boards for monitoring the power as well as a motor that drives the switch to open and close. In short, there’s a lot more that can go wrong.

There are two main reasons as to why a transfer switch needs to be replaced. The most common is an equipment malfunction. This means that switch will either not transfer to generator power or, perhaps, not switch back to utility power. The other reason relates to elevator upgrades.

How could an elevator upgrade impact on the transfer switch?
The transfer switch is able to give the elevator in a condominium a warning before each change of state to allow it to return to a safe location. This ensures a smooth operation and reduces the likelihood that someone will be stuck in an elevator during a transfer. In many cases, the switches cannot be retrofitted to include the pre- and post-transfer option that provides this warning. This unfortunately means that a complete replacement may be the only viable solution in the case of an elevator upgrade.

If the switch is not functioning properly can it be repaired?
In a newer unit we can sometimes replace this board. However, most of these failures are in older switches and parts are no longer available. At this point, you are often left with no other option than a complete replacement.

How much will it cost to replace my transfer switch?
This cost of the replacement will vary depending on the size of the transfer switch and the complexity of the work involved to change it.

Will my building be without power when the transfer switch is replaced?
Replacing your transfer switch will not interrupt the supply of utility power to your building. That means that the suites will have continuous power and most of the lights will remain on.

However, with the transfer switch removed there would be no means of connecting the generator to provide emergency power in the event of a black out. This would leave the building without many of its emergency systems such as fire alarms and elevators during the replacement.

How can we make sure that the emergency power will operate during the switch change?
The solution is a rental generator to provide power to these circuits during the change. While this sounds fairly simple and perhaps obvious, there are a number of factors to consider in the planning stage.

  • The placement of the generator is critical. It is important to avoid disruption to traffic and minimize the noise that may irritate residents.
  • Cables will need to be run to connect the generator to the building’s emergency power. These are often placed in advance to minimize the downtime on the day the work is being done.
  • The rental generator will need an ESA inspection – separate from the transfer switch. This needs to be coordinated in advance to keep the job moving smoothly.
  • The generator needs fuel. If the job takes more than one day, a fuel delivery may be necessary.
  • While the generator is connected and disconnected there will be a disruption of the emergency power.

Are there any other planning issues that need to be considered?
Your contractor will be considering a number of other issues. These points will ensure that you are fully prepared to better qualify the contractor you select for this project.

  • How will the new switch get set in place and how far in advance should it arrive on site?
  • How long will it take to do this job? You need enough labour to meet your projected time line.
  • Who will commission the transfer switch? This needs to be done in conjunction with a qualified generator contractor.
  • Coordinating the ESA inspection for this life safety device prior to start up is a small but critical step.

Have any other questions about transfer switches or their replacement? Get in touch at (416) 490-8093 or @SignatureMark