Fuse taps using the hot side aka wrong side

Nigel

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#41
 

Rajagra

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#42
Both ways are "safe" one is not "safer" than the other.
I'm sorry but one of your own diagrams illustrates the problem, with a 30A fuse leading to the original load and a 5 A fuse leading to the PMP. Meaning the combined current could be 35A from the hot feed.
You could rely on the wiring being higher spec than needed, but it would be an assumption.

Depending what way round the fuse tap goes, the current going to the new accessory can go through either both fuses (lower value blows first) or just the new fuse.
the original circuit is protected regardless of which way the tap is installed
Yes, the original devices are protected as before. But some of the wire leading to the fuse box is less protected than before, if the fuse tap is fitted a certain way.
 

jokiin

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#43
Yes, the original devices are protected as before. But some of the wire leading to the fuse box is less protected than before, if the fuse tap is fitted a certain way.
if you overload a circuit of course you could damage it, unlikely with just a camera and providing the correct size fuses are used, but still something to keep in mind
 

Nigel

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#44
if you overload a circuit of course you could damage it, unlikely with just a camera and providing the correct size fuses are used, but still something to keep in mind
Fuses are there for when things go wrong, not for when things are working as planned. If you tap into a 10A fuse then it is quite likely to be supplied by 10A wire, car manufactures don't put unnecessary copper in the cars as it reduces profits, use a 10A fuse for your new circuit with the tap the wrong way around then it is possible to draw 20A down the 10A wire. Just needs your lithium battery to short out internally while you are using the thing the circuit was intended for and you might have smoke and maybe flames.

The consequences of a car fire can be very nasty, why take any chance, however small, when you can very easily put the tap in the correct and safe way around? It doesn't cost any extra to put it the correct way around, it is not difficult, but it is safer.
 

jokiin

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#45
Fuses are there for when things go wrong, not for when things are working as planned. If you tap into a 10A fuse then it is quite likely to be supplied by 10A wire, car manufactures don't put unnecessary copper in the cars as it reduces profits, use a 10A fuse for your new circuit with the tap the wrong way around then it is possible to draw 20A down the 10A wire. Just needs your lithium battery to short out internally while you are using the thing the circuit was intended for and you might have smoke and maybe flames.

The consequences of a car fire can be very nasty, why take any chance, however small, when you can very easily put the tap in the correct and safe way around? It doesn't cost any extra to put it the correct way around, it is not difficult, but it is safer.
if nothing else you've finally admitted lithium batteries aren't safe
 

Nigel

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#46
if nothing else you've finally admitted lithium batteries aren't safe
They are very safe if used with a correctly installed and rated fuse!
 

Gabacho

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#50
would depend what you wanted to add but I can't see people really adding too much extra equipment for that to become a problem
Thanks for the response. We are working on temporary solutions for rear cameras, and our installer advises to put them on separate circuits and not to exceed three. He does not enjoy my complete confidence so I am looking for other opinions.
 

jokiin

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#51
Thanks for the response. We are working on temporary solutions for rear cameras, and our installer advises to put them on separate circuits and not to exceed three. He does not enjoy my complete confidence so I am looking for other opinions.
depends on the camera and how much it draws I guess, they certainly draw a lot less power than some other accessories you could add that people wouldn't think twice about, CB radios, car fridges etc, you could add 10 of our cameras and they still wouldn't pull the same current as a single car fridge would, I certainly wouldn't suggest overloading any single circuit though regardless
 

Nigel

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#52
Thanks for the response. We are working on temporary solutions for rear cameras, and our installer advises to put them on separate circuits and not to exceed three. He does not enjoy my complete confidence so I am looking for other opinions.
My suggestion would be to use 1 fuse tap on the accessory fuse and use it to power 1 decent quality multi way USB converter such as:



If you install that above the roof liner next to the interior light then you can power the cameras with reasonably short standard USB to micro USB cables and all the wiring is neat.
 

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#53
You could add as many as you can fit. Providing you keep the hot side common to all you could even stack one on top of another. Each subsequent fuse tap would be limited to the size of fuse under it.. The draw of one camera is very low, using 10 amp fuses you could easily stack and run 7 cameras.
 

Rajagra

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#57
You could add as many as you can fit. Providing you keep the hot side common to all you could even stack one on top of another. Each subsequent fuse tap would be limited to the size of fuse under it.
You might need to alternate the orientation of the fuse taps. I.e. the 'output' of one fuse has to feed the 'input' of the one above to get the effect you describe.
It would depend on the construction of the fuse tap. If one was built as shown in the green box of Nigel's diagram that would be great, both for safety and tidiness.

You wouldn't get that effect if you kept the hot side common to all. (As in the red part of the diagram.) That would have the fuses working in parallel, not in series. Each would work independently, and the potential total current would be the sum of the fuse ratings.

 

Ralph2

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#58
I give up on the orientation of fuse taps..:).. Just.. because you have found a colored image does not make it correct.
 

Nigel

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#59
You might need to alternate the orientation of the fuse taps...
Since in most fuse taps, the fuses go at 90 degrees to the originals, you will have to alternate them or they will not physically fit!

They will also build up in a staircase instead of vertical making it difficult to use taps in the adjacent fuses and the stack will probably become rather unstable!
 

Ralph2

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#60
They will also build up in a staircase instead of vertical making it difficult to use taps in the adjacent fuses and the stack will probably become rather unstable!
The whole concept of adding multiple fuse taps is silly :rolleyes:. Use ONE.. and add as many outputs as you like from that ONE pigtail. Add an inline fuse on each leg if you want extra safety.. but it would not be necessary.
 

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