12-way fuse block

 
 
 
 
 
 
Craic Lifer
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Subject:

12-way fuse block

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Posted: 11.10.2019  ·  #1
Morning all.

I recently bought a 12-way fuse block on eBay and by all means, it looks the job.

Last night I wired it up to a 10w COB LED panel to test it out and I noticed something a bit odd. I'm hoping one of you might be able to shed some light... Is it something to worry about or not.

Each fuse has a small red LED indicator next to it and when the fuse blows, this led lights up. A bit gimmicky I know, but I thought it was a handy feature. It works fine, but what I didn't expect is to see a small amount of current still going to the COB led panel when I removed the fuse? I haven't opened up the fuse block yet to see just how this little red LED works.

Any thoughts?

 


Link to the fuse block:
https://www.ebay.ie/itm/1-In-1…2749.l2649


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Re: 12-way fuse block

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Posted: 11.10.2019  ·  #2
There'll be a huge resistor in series with the LED, with the fuse intact and in place, there's no potential difference across the resistor and LED so no current flowing through that branch of the circuit. Does the LED light up when you remove the fuse? The circuitry is unlikely to be able to tell the difference between a removed fuse and a blown fuse unless there is some secondary check for the presence of the fuse.

Your COB should always be switched between the fuse block and the COB and I'd also suggest a kill switch for the power input to the fuse block.


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Re: 12-way fuse block

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Posted: 11.10.2019  ·  #3
Thinking about a little more, the main circuit connection with the blade fuse should be contacts on one side of the fuse legs with the LED circuit contacts on the other side of the fuse legs which will mean that the LED only detects a blown fuse and not a missing fuse, rough schematic to follow...

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Craic Lifer
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Subject:

Re: 12-way fuse block

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Posted: 11.10.2019  ·  #4
Interesting. :up:

I only tried pulling out the fuse to see what'd happen, and the little led indicator light lit up. I didn't try fitting a blown fuse. I'll try that tonight. :D I'm not keen on there still being current at the downline device after the fuse has been removed.


Craic Lifer
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Subject:

Re: 12-way fuse block

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Posted: 11.10.2019  ·  #5
I fitted a led strip light over the hob in my one and when the pump kicks in the led gives the faintest flash for a Milli second (only noticable in the dark)
It is off other than that,


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Re: 12-way fuse block

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Posted: 11.10.2019  ·  #6
Quote by Blag

Interesting. :up:

I only tried pulling out the fuse to see what'd happen, and the little led indicator light lit up. I didn't try fitting a blown fuse. I'll try that tonight. :D I'm not keen on there still being current at the downline device after the fuse has been removed.


Setup seems to be as i described in my first post then. Not what I would do, I'd prefer the LED to indicate blown fuse only and have the missing fuse as the visual indicator of the missing fuse, as described in my second post above.
That said, you should not be pulling fuses to isolate the circuit, that's what switches are for.
Put a switch on the 12v input to the block to allow you to isolate the whole block and put a switch on each output to allow you to isolate the individual circuits.


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Re: 12-way fuse block

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Posted: 11.10.2019  ·  #7
Quote by mad max

I fitted a led strip light over the hob in my one and when the pump kicks in the led gives the faintest flash for a Milli second (only noticable in the dark)
It is off other than that,


Where did you connect to the 12v system? Sounds like a earthing issue.

If the pump and LED share a common ground to the chassis, undo it and clean up any corrosion.

If they don't, there's some resistance between the negative terminal of your battery and the chassis, clean up the battery terminal and connector and undo the earth cable where it connects to the chassis and clean that up.


Craic Lifer
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Subject:

Re: 12-way fuse block

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Posted: 11.10.2019  ·  #8
Yeah good advice.

I should be good with the wiring plan. I have 16mm2 cables running from the leisure battery to the fuse block. On the + wire, I have a 50a "Main" fuse (at the battery) and a 200a "Main" isolator switch to kill the lot if needed. Everything downline of the fuse block will be switched.
The only wires that are still eluding me are the ones that serve all of the original 12v aux sockets in the camper. They're buried in the walls and well hidden. I need to find the wires feeding those, fit a switch, and re-route the wires to the new fuse block. They were not switched originally, but as I'm putting hardwired USB sockets on some of them, I'd like to be able to shut them off.


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