A sudden increase in electrical current isn’t a rare event. Whether through manufacturing errors, wire age or natural forces like storms, electrical current is rarely stable all the time. So, how do manufacturers protect their appliances from this potentially dangerous fluctuation in energy?
Fuses – and by extension their ratings – determine how much current can be channelled through an appliance before a safety protocol is switched on. This safety protects the appliance from damage and reduces the risk of further problems.
So, what is a fuse rating? How does it work and how is it calculated? Below, we discuss all you need to know about fuse ratings, including the role fuse rating labels have.
What is a Fuse Rating?
A fuse is a weak link in an electrical circuit. It may seem odd to design a purposeful weak link but, by choosing where this link is, appliances, people and businesses are kept safe.
When a circuit overloads, the following happens:
- The wire fuse element heats up quickly.
- The fuse then melts or explodes, depending on the current.
- The broken fuse interrupts the flow of electricity.
The conditions for this to happen are dependent on the fuse rating. The fuse rating relates to the strength of current allowed through the circuit, which changes depending on the type of appliance.
If an appliance has a motor, for example, it will have a rating of around 13 Amps, while a more dangerous appliance with a heating element, like a toaster, will have a smaller rating of 7 Amps.
The more potentially dangerous an appliance is, the lower the fuse rating will be.
In the UK, all fuses must be labelled with the correct fuse rating. It’s very important that electrical suppliers both test and label the efficacy of their fuses. If a fuse isn’t labelled correctly, then electricians and other maintenance staff may be in danger as they won’t know what they’re working with.
Without fuses, the risk of electrical injuries and fires would increase tenfold and the health and safety surrounding them would be even more stringent.
How to Calculate a Fuse Rating
Fuse rating calculations need to be exact. To calculate a fuse rating, manufacturers work from a simple equation:
Power (watts) = Voltage x Current (amps)
What we really want to know with this equation is the current (amps). So, using this equation as a basis, the fuse rating can then be calculated with the following:
Amps = Watts / Voltage
So, let’s say we need to work out the fuse rating for a washing machine. It uses 850W of energy at 120V. So, the equation would be:
850/120 = 7.08 amps
This means the washing machine, at maximum energy, would use 7.08 amps of power. So, a 10 Amp fuse would suffice, as that is well over 7.08 amps it produces.
Get Fuse Rating Labels Today
As mentioned previously, calculating fuse ratings alone isn’t enough – you need to label them correctly too.
At Label Source, we stock a range of high-quality fuse rating labels for different ratings. We also stock a range of other electrical labels such as earth symbol labels, which may be of interest.