Extension leads

Photoframe55

I know that when I use my heater, or air purifier, or anything else heavy duty, that it has to be plugged direct into the wall socket.     But,    if the lead is too short,  is there actually a suitable extension lead which can take a heater etc.  ?   
   Also, if you have a double wall socket, is it safe to plug for example, a heater into one and a dehumidifier or something similar into the other plug outlet?  
Thanks for any advice     

prowla

A standard13A extension lead is capable of supporting a number of items being attached provided they don't exceed 13A.

• Each item should say the number of Amps (A) current it draws or kilowatts (kW) power it requires; there's a relationship between Voltage (V), current (A) and power (kW).
• Since the UK mains electricity is 240V the maximum power a 13A socket or extension can support is 13A x 240V = (approx) 3kW.
• Aside from other safety considerations, such as being a trip hazard, susceptible to damage, chewed by the dog, and so-on (which may have been the motivation for the person saying it had to be directly plugged into the wall) an extension lead is fine.
• As for the wall sockets: that depends on the house wiring and the fuses/circuit breakers.
• Looking at the Argos catalogue there's a fan heater rated at 2kW and a dehumidifier rated at 165W; they add up to less than 3kW and so could happily run off a 13A extension.

Other thoughts, caveats, and gotchas...

• An iron on the Argos site is rated at 2.4kW - would you run that off an extension? (NB. you couldn't run it off the same extension as the heater.)
  
• I would be wary of leaving a heater on unattended.
• Don't run an extension lead into the bathroom.
• Is the extension lead is a 13A one? 13A ones are widely available in the shops, but it is possible that a homemade or specialised one could be rated at less (eg. if it was intended for a lamp) or may have a 3A fuse (eg. I have a couple of office-style desk/table extensions which are intended for laptops and suchlike; to reflect their intended use each outputs has a 3A fuse).
  

B0bbyEwing

Just as a FYI - at my work our fridge is plugged in to an extension socket & has been for 8 years. 

Is it right? Doubtful. 

Has it broken, has anyone died, has the world ended - no. 

Section62

prowla said:

A standard13A extension lead is capable of supporting a number of items being attached provided they don't exceed 13A.

• Each item should say the number of Amps (A) current it draws or kilowatts (kW) power it requires; there's a relationship between Voltage (V), current (A) and power (kW).
• Since the UK mains electricity is 240V the maximum power a 13A socket or extension can support is 13A x 240V = (approx) 3kW.
• Aside from other safety considerations, such as being a trip hazard, susceptible to damage, chewed by the dog, and so-on (which may have been the motivation for the person saying it had to be directly plugged into the wall) an extension lead is fine.
• As for the wall sockets: that depends on the house wiring and the fuses/circuit breakers.
• Looking at the Argos catalogue there's a fan heater rated at 2kW and a dehumidifier rated at 165W; they add up to less than 3kW and so could happily run off a 13A extension.

Other thoughts, caveats, and gotchas...

• An iron on the Argos site is rated at 2.4kW - would you run that off an extension? (NB. you couldn't run it off the same extension as the heater.)
  
• I would be wary of leaving a heater on unattended.
• Don't run an extension lead into the bathroom.
• Is the extension lead is a 13A one? Almost all which can be purchased in the shops are 13A, but it is possible that a homemade one could be rated at less (eg. if it was intended for a lamp) or may have a 3A fuse (eg. I have a couple of office-style desk/table extensions which are intended for laptops and suchlike; to reflect their intended use each outputs has a 3A fuse).
  

Lots of shop/online ones are only rated at 10 amps and fitted with a 10A fuse.  Just as an example -

https://www.argos.co.uk/product/4136798?clickPR=plp:5:30

And just because one is described/labeled as "13A" doesn't necessarily mean it is. For example, the blurb for this one suggests it is 2A maximum - I'd guess the person responsibile for writing the blurb was looking at the USB spec rather than the rating of the cable, but that would need checking. (the point being that 'blurb' can't always be relied on, especially when buying cheap leads from online sources)

https://www.argos.co.uk/product/3209248?clickPR=plp:4:6

The nominal voltage in the UK has been 230V since 2003.  The tolerance around that figure means in normal conditions the supply could vary from 216V to 253V.  In abnormal conditions the suppliers are allowed to reduce the voltage further.  To supply the same power at a lower voltage a higher current would need to be drawn.  In most cases that probably doesn't matter much, but if someone has maxed out the load on their extension lead assuming the voltage was 240V then the lead could be overloaded if the true voltage of their supply was only 220V.

Plugging a heavy load into a suitably rated extension lead may be Ok in the right circumstances, but there are so many variables that the generic advice not to do so is good advice.

Section62

B0bbyEwing said:

Just as a FYI - at my work our fridge is plugged in to an extension socket & has been for 8 years. 

Is it right? Doubtful. 

Has it broken, has anyone died, has the world ended - no. 

Other than when the compressor motor starts, a fridge has a relatively low current demand.  The compressor start should normally be very brief.

That is a very different situation to plugging a multi-kW heater into an extension lead and leaving it switched on for some time.

prowla

Section62 said:

prowla said:

A standard13A extension lead is capable of supporting a number of items being attached provided they don't exceed 13A.

• Each item should say the number of Amps (A) current it draws or kilowatts (kW) power it requires; there's a relationship between Voltage (V), current (A) and power (kW).
• Since the UK mains electricity is 240V the maximum power a 13A socket or extension can support is 13A x 240V = (approx) 3kW.
• Aside from other safety considerations, such as being a trip hazard, susceptible to damage, chewed by the dog, and so-on (which may have been the motivation for the person saying it had to be directly plugged into the wall) an extension lead is fine.
• As for the wall sockets: that depends on the house wiring and the fuses/circuit breakers.
• Looking at the Argos catalogue there's a fan heater rated at 2kW and a dehumidifier rated at 165W; they add up to less than 3kW and so could happily run off a 13A extension.

Other thoughts, caveats, and gotchas...

• An iron on the Argos site is rated at 2.4kW - would you run that off an extension? (NB. you couldn't run it off the same extension as the heater.)
  
• I would be wary of leaving a heater on unattended.
• Don't run an extension lead into the bathroom.
• Is the extension lead is a 13A one? Almost all which can be purchased in the shops are 13A, but it is possible that a homemade one could be rated at less (eg. if it was intended for a lamp) or may have a 3A fuse (eg. I have a couple of office-style desk/table extensions which are intended for laptops and suchlike; to reflect their intended use each outputs has a 3A fuse).
  

Lots of shop/online ones are only rated at 10 amps and fitted with a 10A fuse.  Just as an example -

https://www.argos.co.uk/product/4136798?clickPR=plp:5:30

And just because one is described/labeled as "13A" doesn't necessarily mean it is. For example, the blurb for this one suggests it is 2A maximum - I'd guess the person responsibile for writing the blurb was looking at the USB spec rather than the rating of the cable, but that would need checking. (the point being that 'blurb' can't always be relied on, especially when buying cheap leads from online sources)

https://www.argos.co.uk/product/3209248?clickPR=plp:4:6

The nominal voltage in the UK has been 230V since 2003.  The tolerance around that figure means in normal conditions the supply could vary from 216V to 253V.  In abnormal conditions the suppliers are allowed to reduce the voltage further.  To supply the same power at a lower voltage a higher current would need to be drawn.  In most cases that probably doesn't matter much, but if someone has maxed out the load on their extension lead assuming the voltage was 240V then the lead could be overloaded if the true voltage of their supply was only 220V.

Plugging a heavy load into a suitably rated extension lead may be Ok in the right circumstances, but there are so many variables that the generic advice not to do so is good advice.

Thanks for the extra info - I rounded 13 x 24 = 3000 to cover fluctuations.

I'll amend my wording re. the "Almost all".

Robin9

If the extension lead is on a drum make sure it is fully unwound.  If not it will get hot and may cause a fire - we had a double fatality locally.

onomatopoeia99

Section62 said:

The nominal voltage in the UK has been 230V since 2003.  The tolerance around that figure means in normal conditions the supply could vary from 216V to 253V.  In abnormal conditions the suppliers are allowed to reduce the voltage further.  To supply the same power at a lower voltage a higher current would need to be drawn.  In most cases that probably doesn't matter much, but if someone has maxed out the load on their extension lead assuming the voltage was 240V then the lead could be overloaded if the true voltage of their supply was only 220V.

A heater or an iron is basically a resistive load, so a supply votage reduction will result in an equivalent current reduction per Ohm's law, not an increase.

I'm trying to work out what high current devices that could be attached to a 13A plug are not resistive loads and draw constant power irrespective on input voltage.

Bigphil1474

OP, I have an 8 plug extension lead that has my laptop, monitor, electric heater, amazon echo, air compressor, and a lamp plugged in. Not all on at once, but it's not an issue based on the info supplied with the extension lead. Would prefer if everything was plugged into the wall, but I only have 2 plugs and the wi-fi is plugged into one. The heater is only on if I'm sat next to it.