Hi guys, I discovered that the number 40 fuse for the 12v sockets had blown, and I’m not sure what amp fuse to replace in there.

 

The blown fuse was a 20 amp, but the reason I’m asking if I should definitely fit a 20 amp replacement is because I’m powering a number of extra devices off the front socket (cigarette lighter) as follows:

4-way 12v cigarette lighter splitter powering:

1. 10 inch CarPlay monitor

2. 4K Dashcam

3. USB adapter to MagSafe iPhone charger

4. USB adapter for rear seats

 

I’m afraid I don’t know enough about electrics to know if a 20 amp fuse is appropriate for all this, so your expert help is greatly appreciated!

 

I should also say, the male part that goes into the front 12v socket has its own fuse in the barrel for an added layer of safety.

 

Thanks so much in advance.

Hello Abbey, welcome to the forum. Very strongly advise to fit only correct rated fuse to any circuit.

Unless the actual capacity of the circuit wiring is known, there is a very real risk of overheating and fire if the current capacity of wiring is exceeded. 

The fuse is to protect the car's wiring (and appliances), if you are using too much electric through the fuse it melts because of the heat, or the fuse may quickly/instantly "blow" if there is a fault in the wiring or appliances.

 

Different appliances can use different amounts of electricity and possibly at different times, some may have a surge when switched on or they switch something on within  themselves and this may cause an overload to the fuse.

 

You could think of the fuse like a string tied to a hook with the string holding some weight or weights at the end of it, if you add too much weight the string breaks.  If you put in a fuse too strong (higher amps) then if it does not melt or "blow" then all the load is on the wiring and the wiring can overheat.

 

HTH.

 

Edited 20 September, 20241 yr by nta16
missing words

There's a previous discussion, where Pete confirmed it should be a 20A fuse:

 

 

Gaz

You could be overloading the socket and it's fuse with too much going through it with all you have plugged into it, or one (or more) of the items could have a fault in it or its wiring, this could be in -

1. 4-way 12v cigarette lighter splitter
2. 10 inch CarPlay monitor
3. 4K Dashcam
4. USB adapter to MagSafe iPhone charger
5. USB adapter for rear seats - or whatever is/are plugged into this.

Thank you all, that's really helpful stuff. I will put a 20 amp fuse back in there!