Wiring in +/- into car fuse (piggyback)

[ChrizK]

You can use various size fuses branching off the supply to the original fuse, that cable must be able to handle the total load.


5 amp will be fine.

'total load' has thrown me, I believe the cable being the cable from the tap/piggyback (...plus my extension).

If I were to tap into a position containing a 10Amp (original), for a 5Amp device, therefore using a 5Amp 'piggyback fuse', I am guessing the cable must be able to handle the total load/draw of that device, being 5Amp (otherwise the fuse would blow).

Sorry, I am sure your answer makes perfect sense to anybody with knowledge, but I need things spelt out so that I understand the basics.

 

[DPG]

'total load' has thrown me, I believe the cable being the cable from the tap/piggyback (...plus my extension).

If I were to tap into a position containing a 10Amp (original), for a 5Amp device, therefore using a 5Amp 'piggyback fuse', I am guessing the cable must be able to handle the total load/draw of that device, being 5Amp (otherwise the fuse would blow).

Sorry, I am sure your answer makes perfect sense to anybody with knowledge, but I need things spelt out so that I understand the basics.

The new device's load needs to be less than the 5A rating of the new piggyback fuse that is feeding it. The cable used needs to be able to handle 5A.

 

[mainline]

'total load' has thrown me, I believe the cable being the cable from the tap/piggyback (...plus my extension).

If I were to tap into a position containing a 10Amp (original), for a 5Amp device, therefore using a 5Amp 'piggyback fuse', I am guessing the cable must be able to handle the total load/draw of that device, being 5Amp (otherwise the fuse would blow).

Sorry, I am sure your answer makes perfect sense to anybody with knowledge, but I need things spelt out so that I understand the basics.

You have 2 choices when connecting a new circuit to an existing fuse.

1) You join to the cable that supplies the existing fuse and add your own fuse for your extra circuit.

2) you join to the outgoing side of the original fuse with your own fuse.

1) would be the correct way.

2) would be adding an extra load to the existing fuse.

Whichever way you do it, you will be adding an extra load to the cable that feeds the original fuse.