Being Prepared, Spare Fuses


Last month I received a request from a property manager for pricing on a fairly long list of fuses. Clearly this was an order for a stock of spare fuses to be stored on site. Signature-electric-spare-fuses

I was truly impressed. Here’s a manager that’s thinking ahead.

Inevitably at some point a fuse is going to blow. These fuses are protective devices sized to the load and wire gauge to protect the equipment and associated wiring from damage or fire in the event of an overload or short circuit. They range in size from a few to many hundreds of amperes and are available in a variety of voltage and sensitively levels.

 As I said the question is not if, but when will a fuse blow. Hopefully it will happen during the normal working day, the source of the problem will be easy to identify and your electrical contractor will be nearby with a spare fuse and expertise to rectify the issue in a timely manner.

 As we all know too well, this lovely scenario does not always play out as I just described. We all hope that our electrical contractor will be available when we call, but what about the fuses? While they may have a spare on the truck, due to the large range of fuse size and types it’s not realistic to expect them to carry every fuse that might be needed for all situations.

At least during that day we can rely on our wholesalers to provide us with replacements. However even a trip to the supplier adds to the cost and extends the time necessary to restore the power. A blown fuse at night just magnifies these costs. We may now have have a premium labour charge, and while fuses can be obtained outside of normal business hours this also comes with extra costs and time.

The solution that I’m suggesting is that each building maintain a stock of fuses in their main electrical room for use at any time. These should be housed in a cabinet mounted to the wall and, ideally locked. The key should be held at the security desk and there should be some signage at the cabinet directing the electrician to the location of the key at security.

I’m guessing that you may be curious now. Wander down to the electrical room and see what the situation is in your building.


  1. A fully stocked and locked cabinet marked, “spare fuses”  with an typed inventory list maintained on the outside and the inside of the cabinet and signage directing you to where the key is kept?

  2. A cabinet on the wall with some fuses in it?

  3. A few fuses in a box on the floor?

  4. A cabinet with no fuses in it?

  5. No fuses and no cabinet?

I’m sure that I don’t have to tell you that it’s extremely rare for me to see a “1”. How did your building rate? If you want to get to (or at least closer to ) #1, here’s what I suggest.

Give me a call at 416-490-8093 or send me an email

  • We can review your present situation.

  • Determine what quantity of fuses and types might be suitable for your building.

  • Provide special bulk pricing for your fuses with free delivery to your site.

  • Provide pricing for a fuse cabinet if required.

  • Send you an inventory list of these fuses that you can post at your cabinet

  • Install and stock your cabinet for you.

A Word of Caution

These fuses are to be installed only by a trained professional. The voltages present in these switches are lethal. There’s usually no visual indication of which fuse or fuses have blown. You must verify voltages on both the line and load side of the switch to confirm if the issue is upstream from this device and as well to confirm that the switch itself has opened properly. Again in most cases these items cannot be confirmed by a visual inspection.

It’s also important to determine the cause of the blown fuse. It can be dangerous to change a fuse and close a switch with a short circuit on the line.

This may not really be the right job for your on site superintendent.