Thread: A few quick questions re electronics

Originally Posted by VladTepes

1. Can cable glands cope with >1 cable or would you need one per 'cable'?

Only if you don't need it to be watertight.

2. Can you join a thing gauge wire to a thicker gauge wire? If so, best way?

Depends on what you are doing, but in general, yes, and in my view twisting together and soldering with a heat shrink tube over the join topped with amalgamating tape.

3. Ok to 'daisy chain' earths from one carling switch to another? Idea being to have 2 cables twisted together crimped into each spade plug in the chain.

Yes, provided the total current is not too large for the wire. But special considerations apply for audio or RF frequencies.

4. What type of relay to use for LED floods / lightbar etc?

Automotive type with adequate current capacity. Known brands are probably best!

Oh and I'm still chasing a good (inexpensive ideally) source for all these components. Local might be best - the chinese ebay ones are probably poor quality.

No doubt more questions will be forthcoming.

Can't help with source, and opinions may vary - bit hard without knowing exactly what you are doing.

John

1. yes,but as mentioned they wont be ingress tight but you can get multi cable grommets and you can use packing matrial it depends no why you are using the grommet if its just for protection of the cable so long as the grommet isnt compromised you're good to go.

2. yes, the bst way varies as to the "why are you doing it?" Usually if you're joining thin to thick you'll be running a circuit from a feed, this is an ideal point to terminate both cables correctly and use a joiner, like a fuse or waterproof connection which gives you an access point for diagnostics later.

3. yes, as mentioned keep in mind total current and load sequence you can get some interesting effects if you're approaching the current limit of the final earth wire with all of the hardware turned on.

4. Narva, most stuff off of the shelf in a truck shop, jaycar,altronics, supercheap and repco remember theres a number of different configurations (including all those variations with internal diode, fused, suppressed, high current, and combinations thereof) for the "standard" 5 pin relay and then theres propratory configurations of relays that look the same but are not built to the standard.

Im guessing your looking at adding led light bars and working lights and want to join them into existing systems.

Thanks all, keep the advice coming.


To clarify a few things (for everyone) I've answered Dave's points below.

Originally Posted by Blknight.aus

1. yes,but as mentioned they wont be ingress tight but you can get multi cable grommets and you can use packing matrial it depends no why you are using the grommet if its just for protection of the cable so long as the grommet isnt compromised you're good to go.



Hmm, the whole idea of a compression seal / sealing gland (which is what I want to use) is to allow a cable to pass through a panel and keep water OUT. Last thing I want is H2O dripping from the roof inside the cab.

2. yes, the bst way varies as to the "why are you doing it?" Usually if you're joining thin to thick you'll be running a circuit from a feed, this is an ideal point to terminate both cables correctly and use a joiner, like a fuse or waterproof connection which gives you an access point for diagnostics later.


The existing cable into the small LED light is VERY thin. I just need to extend the cable, which will be using the standard gauge automotive wire. A normal electrical joiner is no use as the cable to the lights is too small, so the twist, solder, shrink wrap is possibly the best method. If I can get the wrap to shrink without burning through the insulation! Cheap LED lights those ones but they do the job. I'll show you all once its all done.

3. yes, as mentioned keep in mind total current and load sequence you can get some interesting effects if you're approaching the current limit of the final earth wire with all of the hardware turned on.



The total current should be pretty small - 7 carling switches. The idea is that for most of them the switch will control a relay to supply 'proper' power as opposed to having the current run via the switch.

4. Narva, most stuff off of the shelf in a truck shop, jaycar,altronics, supercheap and repco remember theres a number of different configurations (including all those variations with internal diode, fused, suppressed, high current, and combinations thereof) for the "standard" 5 pin relay and then theres propratory configurations of relays that look the same but are not built to the standard.


Oh jeez, who knew it was so complex? The use is as described above. 6 of the switches are simple on/off type.

Im guessing your looking at adding led light bars and working lights and want to join them into existing systems.


Yep

What about these for a water resistant plug?


Automotive Waterproof Plug & Socket Set - 6 way | Automotive | Plugs, Sockets & Adaptors | Interconnect | PRODUCTS | PP2116 | Jaycar Electronics


Doesn't say what min/max size cable though - just amperage rating.

PLUGS

I am looking for a solution that can carry 20A for one cable at 10A (or 7.5A) for 2 other cables. Ideally I'd like a flush mount socket, which will face the outside of the vehicle. Waterproof / resistance highly desirable.

The only solution I've seen so far is one of those trailer plugs but its so monstrous and the plug projects so far is just not ideal at all.

If no flush mount available....


Again:

Originally Posted by VladTepes

What about these for a water resistant plug?


Automotive Waterproof Plug & Socket Set - 6 way | Automotive | Plugs, Sockets & Adaptors | Interconnect | PRODUCTS | PP2116 | Jaycar Electronics


Doesn't say what min/max size cable though - just amperage rating.

Have a look at a marine chandler - they specialise in "waterproof".

John