Home Button

Prices Button

Services Offered Button

About Us Button

Contact Us Button

Where We Are Button

Domestic Electrical Button

Commercial Electrical Button

Search This Site Button

Site Map Button

Fuse Rating

This web page explains fuse ratings.

 

This web page answers the questions:

  • What are typical fuse ratings?
  •  

  • How to calculate the fuse rating.
  •  

  • What is a fuse rating?
  •  

  • Why are fuses rated?

 

Typical Fuse Ratings

  • Clock radio – 3 amp.
  •  

  • Coffee maker – 5 amp.
  •  

  • Dishwasher – 13 amp.
  •  

  • DVD player – 3 amp.
  •  

  • Electric blanket – 3 amp.
  •  

  • Fan – 3 amp.
  •  

  • Food mixer – 3 amp.
  •  

  • Fridge – 3 amp.
  •  

  • Hair dryer – 13 amp.
  •  

  • Hi-fi – 5 amp.
  •  

  • Iron – 13 amp.
  •  

  • Kettle – 13 amp.
  •  

  • Lamp – 3 amp.
  •  

  • Laptop PC – 3 amp.
  •  

  • Microwave oven – 5 amp.
  •  

  • PC – 3 amp.
  •  

  • Radio – 3 amp.
  •  

  • Table lamp – 3 amp.
  •  

  • Toaster – 5 amp.
  •  

  • TV – 3 amp.
  •  

  • Vacuum cleaner – 3 amp.
  •  

  • Video player – 3 amp.
  •  

  • Washing machine – 5 amp.

Judge Electrical fuses home page

 

 

How To Calculate The Fuse Rating

Using the guideline that the fuse is rated at 125% of the normal operating current.

 

Power (Watts) = Current (Amps) x Voltage (Volts)

 

Therefore:

 

Current = Power/Voltage

 

Therefore:

 

Fuse rating = (Power/Voltage) x 125%

OR, put another way:

 

Fuse rating = (Power/Voltage) x 1.25

OR, put another way:

 

Fuse rating = (watts/volts) x 1.25

 

  • Note the power of the appliance – usually in the appliance manual,
  • Note the voltage (240 volts in the UK).
  • Use the next highest fuse rating after the calculation.
    • Say the calculated fuse rating is 2.2679 amps, use a 3 amp fuse.
    • Say the calculated fuse rating is 4.9431 amps, use a 5 amp fuse.
    • Say the calculated fuse rating is 8.9032 amps, use a 13 amp fuse.
    • Say the calculated fuse rating is 10.6421 amps, use a 13 amp fuse.

 

Fuse Rating Calculations

The assumption in this calculation is that their are only 3 fuse ratings, 3 amp, 5 amp and 13 amp.

 

Say the power is 500 watts.

Fuse rating = (watts/volts) x 1.25

Fuse rating = (500/240) x 1.25

Fuse rating = (2.083333333) x 1.25

Fuse rating = 2.604166667 amps

Next fuse up is a 3 amp fuse, use a 3 amp fuse.

 

 

Say the power is 200 watts.

Fuse rating = (watts/volts) x 1.25

Fuse rating = (200/240) x 1.25

Fuse rating = (0.83333333) x 1.25

Fuse rating = 1.04166667 amps

Next fuse up is a 3 amp fuse, use a 3 amp fuse.

 

 

Say the power is 1500 watts.

Fuse rating = (watts/volts) x 1.25

Fuse rating = (1500/240) x 1.25

Fuse rating = (6.25) x 1.25

Fuse rating = 7.8136 amps

Next fuse up is a 13 amp fuse, use a 13 amp fuse.


 

Say the power is 900 watts.

Fuse rating = (watts/volts) x 1.25

Fuse rating = (900/240) x 1.25

Fuse rating = (3.755) x 1.25

Fuse rating = 4.6875 amps

Next fuse up is a 5 amp fuse, use a 5 amp fuse.

 

 

Judge Electrical fuses home page

 

 

What Is A Fuse Rating?

A fuse rating is the current need to blow (break) the fuse.


When a fuse has blown it removes electrical power from an electrical circuit.

The fuse rating is usually on the side of the fuse.

The fuse rating is usually defined in ‘amps’ – amps are the unit of measurement of electrical current.
Miles are a unit of measurement of distance, Celsius are a unit of measurement of temperature, amps are the unit of measurement of electrical current.

 

Fuse with fuse rating highlighted

Judge Electrical fuses home page

 

 

Why Are Fuses Rated?

Fuses have different ratings so they can protect different electrical circuits.

Different electrical circuits use different amounts of electrical current – what may be too much electrical current for one electrical circuit may not be too much for a different electrical circuit.

A fuse that blows at, say, 10 amps is no use in an electrical circuit that uses 12 amps – the fuse would blow during normal circuit working.

A fuse that blows at 10 amps is no use in an electrical circuit that is using too much electrical current at 5 amps. The electrical circuit would be using double the ‘safe to use’ electrical current before the fuse blows.

 

Judge Electrical fuses home page

   

 

Judge Electrical Limited
15 Mulberry Court, Huntington, York, YO32 9TU
Telephone 01904 764845 (Landline), 07919 033113 Mobile)
Email info@judgeelectrical.co.uk
VAT No. 852917405. Company Number 6359328