Fuses for LED readouts - a wiring query

[Grace and Favour]

May I ask for a little advice please

 

I'm fitting some LED readouts, (very low amperage - 0.02A) - and will have each of them drawing power from two choc-blocks (wired as mini-bus-bars if you will) - mounted on a back-board

 

The multi-strand cable to each of the LED's is very small, of course, and I'll be using 2mm² cabling to provide the power to the choc-blocks.

 

I believe I should fit individual fuses to (0.02A) each of the readouts, as their cables are much smaller than the 2mm² supply (which will also be fused ) - - -

 

Question - Am I correct in my process above?

 

Thanks

 

Dave

 

 

[nicknorman]

Why not just fit the fuses at the suupply end of the thicker wires so that you have one fuse for both sets of wires (or do the thicker wires power something else as well?) 20mA sounds a pretty small fuse to me, I wonder if its filament might fail due to vibration over time. Surely the wires can't be that thin, and so a somewhat larger fuse say 200mA could be used.

[Grace and Favour]

Well - - I was planning on having one supply wire to the 'bus-bars' (choc-blocks) - which would be fused - thus protecting that cabling.

But that fuse would be too substantial for the individual LED's supplies coming off the bus-bar - which is why I thought each would have to be fused.

 

with this type of fuse

[nicknorman]

Are you sure that isn't a capacitor! Anyway, you didn't quite answer my question about whether the 2mm wires are supplying anything else. If not, there is no harm in protecting the 2mm cable with a low current fuse (eg 200mA) which will also protect the LED wires. No point in having more fuses than necessary (especially if they are in fact capacitors!)

[Keith M]

May I ask for a little advice please

 

I'm fitting some LED readouts, (very low amperage - 0.02A) - and will have each of them drawing power from two choc-blocks (wired as mini-bus-bars if you will) - mounted on a back-board

 

The multi-strand cable to each of the LED's is very small, of course, and I'll be using 2mm² cabling to provide the power to the choc-blocks.

 

I believe I should fit individual fuses to (0.02A) each of the readouts, as their cables are much smaller than the 2mm² supply (which will also be fused ) - - -

 

Question - Am I correct in my process above?

 

Thanks

 

Dave

 

 

 

With the very thin wires it will be best to use cable end ferrules when fitting the wires to terminal strip

 

Keith

 

Keith

[Chalky]

The standard for automotive wiring is that the fuse is sized to protect the wiring, not the load. If you're using 2mm csa cable then this will set the fusing requirement.

[Grace and Favour]

Are you sure that isn't a capacitor! Anyway, you didn't quite answer my question about whether the 2mm wires are supplying anything else. If not, there is no harm in protecting the 2mm cable with a low current fuse (eg 200mA) which will also protect the LED wires. No point in having more fuses than necessary (especially if they are in fact capacitors!)

AH! - - Now I understand - - - -- thanks Nick (numpty I am)

 

 

With the very thin wires it will be best to use cable end ferrules when fitting the wires to terminal strip

 

Keith

 

Keith

Aye - I'll be using bootlace ferrules - thanks Keith

 

 

The standard for automotive wiring is that the fuse is sized to protect the wiring, not the load. If you're using 2mm csa cable then this will set the fusing requirement.

Thanks Chalky - - that's as I understood it...... I appreciate your confirmation

 

 

 

Thanks all, I now know what I should do . .

[nicknorman]

The standard for automotive wiring is that the fuse is sized to protect the wiring, not the load. If you're using 2mm csa cable then this will set the fusing requirement.

 

However, when the wiring gets thinner further down (as it is in this case) then it makes sense to select a fuse that is the right size for the thin wiring, and too small for the fat wiring, assumings its current will be low.