Wiring help

[NiceCupOfTea]

I'm wiring up a couple of dials in the MX-5 - tapping into the stereo loom as easily accessible live/switched live/lights wires.

Just realised that the fuses in the fuse box of 15A for fag lighter/stereo switched live, and 10A for all sorts of other bits and permanent live.

I have got 5A cable/chocblocks/scotchloks.

Is it:

• fine and I'm being a fanny
• potentially dangerous and I should use 15A cable/bits

[Simon_m]

15A cable and choc blocks as there is potential for the cable etc to melt before the fuse

[NiceCupOfTea]

As I feared Back to Halfords tomorrow

[Simon_m]

Where are you? I could let you have some for free

[WhoseGeneration]

NiceCupOfTea said:

I'm wiring up a couple of dials in the MX-5 - tapping into the stereo loom as easily accessible live/switched live/lights wires.

Just realised that the fuses in the fuse box of 15A for fag lighter/stereo switched live, and 10A for all sorts of other bits and permanent live.

I have got 5A cable/chocblocks/scotchloks.

Is it:

• fine and I'm being a fanny
• potentially dangerous and I should use 15A cable/bits

Few issues here, what are the dials?, you needing power for their function or merely their illumination?
If only illumination, surely you only want that when lights are on?
So, you need to tap the instruments illumination circuit and consider the current draw of the lighting in your dials, to determine the wiring gauge, that too depends upon what wire you are using, boggo or specific auto wire, and whether that, added to the standard fit exceeds the fitted fuse for that.
Please don't use chocblock or scotchloks.
Use proper crimp connectors and, preferably, cover them with heatshrink sleeving.
This all assumes your MX 5 is pre canbus and body control module stuff.

[NiceCupOfTea]

Mk.1, so pre canbus.

clock (permanent live, earth, lights)
water temp (switched live, earth, lights, sender)

I hate crimped connectors, they never seem to hold together for me. And trust me, scotchlocks are a lot better than my soldering

Kind offer Simon, I am in Bromley if you are nearby?

[WhoseGeneration]

NiceCupOfTea said:

Mk.1, so pre canbus.

clock (permanent live, earth, lights)
water temp (switched live, earth, lights, sender)

I hate crimped connectors, they never seem to hold together for me. And trust me, scotchlocks are a lot better than my soldering

Kind offer Simon, I am in Bromley if you are nearby?

Clock, permanent live, from a permanent live at the fusebox, or, if using say the cig lighter, with an inline fuse, earth to chassis earth point behind dash or tap any earth cable. Lights, as I said, tap instrument lighting.
Water temp, switched live, from any switched live to the instruments, earth and lights as above, sender cable is best fed through any existing cable sheath or, if not possible, get some for this cable.
Crimpimg, get a ratchet crimper and always use the correct size connector for the cable you are using.
Scotchloks, to me, shout amateur.
All the connectors in your car are crimped.
Although, some of us can solder connections, that last, in car wiring.
There has been some debate here about whether car wiring can be soldered.

[dilbert]

If you're tapping into a 15A wire, and your load is only 5A, then it's fine.
What you will need to do, is to put a 5A fuse into the new circuit that you add in.
All you need do, is use one of those inline plastic fuseholders.

Edited by dilbert on Friday 6th August 00:48

[NiceCupOfTea]

Yes, but I am an amateur

I don't really see the benefit from taking lights/switched live from behind the dash or live from the fusebox, it creates a huge amount of extra work and seems much neater just to tap into the radio loom where the wires are already and where they are already fused. Earth is going to a chassis point.

As long as the wires/connections are rated higher than the fuse it should be OK I think.

Actually already decided to buy a ratchet crimper tomorrow!

[WhoseGeneration]

NiceCupOfTea said:

Yes, but I am an amateur

I don't really see the benefit from taking lights/switched live from behind the dash or live from the fusebox, it creates a huge amount of extra work and seems much neater just to tap into the radio loom where the wires are already and where they are already fused. Earth is going to a chassis point.

As long as the wires/connections are rated higher than the fuse it should be OK I think.

Actually already decided to buy a ratchet crimper tomorrow!

Don't mind me, I really shouldn't get involved in any "how to do it" threads, because what I really want to say is, bring it round to my place and we'll do it together.
Just that I like to do any additions such that they look like manufacturer fit.

[Simon_m]

NiceCupOfTea said:

Mk.1, so pre canbus.

clock (permanent live, earth, lights)
water temp (switched live, earth, lights, sender)

I hate crimped connectors, they never seem to hold together for me. And trust me, scotchlocks are a lot better than my soldering

Kind offer Simon, I am in Bromley if you are nearby?

I am in North Wales near to Mold so not too close I'm afraid. I wouldn't bother with Halfords, Maplin is far cheaper. As others have said choc blocks do look a bit amateur they do the job however. If you are getting a crimping tool you may as well get some male and female spades and some heatshrink, these can be had for peanuts at Maplin and are dead easy to use.

[fatboy b]

Scotchloks

[NiceCupOfTea]

WhoseGeneration> I appreciate the thought! I used to be a perfectionist but I learned a long time ago to settle for being a realist.

fatboy> People always piss and winge about scotchloks but I've never had a problem with them. The alternative is cutting the wire completely and soldering both ends and the new spur together and covering in heatshrink. As I said, if you had ever seen my soldering you would realise that scotchloks are a much better, safer, and tidier solution

[Superhoop]

I'm not far from you Orpington/Locksbottom), and would be happy to give you a lesson in soldering if you like