UCL has a general aim to not use extension leads if possible, as they can be a significant fire risk if used incorrectly. It is understood that it is sometimes necessary to use extension leads as wall mounted power sockets are not always in suitable positions and having additional sockets fitted can be difficult and take sometime. However, wall mounted power sockets are the favoured method of providing power and should be requested where long-term use of extension leads is occurring.
Electrical extension leads are not a direct replacement for a wall socket. Extension leads have a 13 amp or less rating and wall sockets a 30 amp rating. This means it is much easier to overload an extension lead, which is likely to lead to a fire.
In the use of extension leads, what is plugged in is more important than how many items. Multiple low amp items may be fine, but one high amp item, such as an electric heater, is likely to overload the lead and cause a fire.
The total ampage of the items plugged into the extension lead must be less than the rating of the lead, usually 13 amp (See table at the bottom of this blog). Check your extension cables for their rating, usually listed on the back.
Have a look at the Electrical Safety First webpage and try their Socket Overload Calculator:
- Use wall sockets if possible
- Use extension leads with an earth – three cable leads
- Visually check leads for cuts, broken plastic cover or exposed wires – discard if any found
- Ensure leads do not create a trip hazard
- Use double insulated leads – these will have a symbol with a square within a square and do not have an earth
- Daisy chain leads, linking more than on lead together is very dangerous
- Use reel extension leads – these are banned on all UCL sites as they are dangerous if improperly used. please dispose of any reel extension leads you may have
This is a simplified explanation and if you are unsure, plug it into the wall. I am happy to give more detailed advice about individual issues.
Table of common electrical equipment
|Domestic Portable Appliance||Amps Used||Watts Used|
|Laptop||<0.5||65 – 100|
|Mobile phone charger||<0.5||<12|
|Satellite TV box||<0.5||30|
|Landline cordless telephone charger||<0.5||10|
|Television 42″ HD||0.5||120|
|Radiator (oil filled)||13.0||3000|