Cable runs in conduit, induction & interference?

colcreate · 29 March 2013, 10:17

After a long break (operation, work, life, too wet/cold and other excuses) I have finally got round to finishing off my Searider. Determined to get it on the water this year!!
Started doing the wiring and rigging and want it all neat and tidy with everything running through 2" corrugated tubing from console to transom.

Question is though, is there anything that shouldn't be run together? Fuel line, hydraulics, VHF, sounder, gps, battery cables, engine loom, nav lights?

I'm thinking there may be cross interference between all the signals running up and down a tightly packed line.

Should I split the runs down two separate tubes?

Erin · 29 March 2013, 10:37

Theoretically there is a fairly good chance of interference, particularly between high frequency cables such as the VHF and sounder. However in reality you may be lucky and not suffer. Best you can do is give it a try. My VHF and sounder wires share the same conduit and live happily together.

Pikey Dave · 29 March 2013, 11:02

Wot Erin said

In addition, you might get interference from the alternator via the battery leads. This usually manifests itself as a high pitched whine on the VHF that varies with engine speed. In reality it's a suck it & see jobby . Make sure everything is well earthed, good tight battery connections, good connections on VHF antenna etc.

colcreate · 29 March 2013, 11:16

'Plan A' was suck it and see, Erin's turned out OK so that's one vote in favour.
Looks like it's going to be two separate runs anyway as I have just seen the sizes of loom connectors and hydraulic nuts that will need to be routed through. In addition to 18mm OD Iso fuel hose and two runs of 35mm battery cable and the two control cables that I forgot about.... Doh!
I had that insessant whine on the radio with my last rib, but took the handheld off the wife so she can't call me now! Fixed!
Just talked to a mate about this, he had problems with his Structure scan imaging until he re routed the transducer wire away from his battery cables. So that's one vote against.

martini · 29 March 2013, 12:16

I never had any problems with interference, not in underfloor conduits at least.

My advice would be use 2 conduits anyway, you always need far more than you think, guaranteed.

BruceB · 29 March 2013, 13:21

I ran a single conduit which includes VHF, battery leads, twin sounders, GPS, AIS, Floodlight and nav lights and didn't get any interference.
Suck it and see.

Nos4r2 · 29 March 2013, 13:32

Quote:

Originally Posted by martini

I never had any problems with interference, not in underfloor conduits at least.

My advice would be use 2 conduits anyway, you always need far more than you think, guaranteed.

Seconded. I've got more on the deck of my 5.4 than would fit in 2 2" conduits and all I've got is engine wiring,nav lights VHF and control cables.

9D280 · 02 April 2013, 11:07

Ditto!

I am nuw up to 4 - but that was more down to tidy routing & trip hazard! I reckoned that 4 smaller conduits would be a flatter less trippable run than one big dia one.

Form memory I have everything going to the A- frame in one (Nav lights, NMEA2K for the plotter antenna & 2x VHF aeriel (one a spare / wil lbe AIS in the fullness of time - patchable inside the console) One with the engine control / PT & sounder cables, one with the Main engine power & one with fuel. (Only because the fuel hose doesn't leave much space for anything else).

They are all alongide each other across the deck, no interference on anything so far...

simonc2409 · 07 April 2013, 10:42

I keep fuel and power separate on my Searider so the fuel line runs down the left side and power and everything else the right side. I haven't needed a conduit as most of the instrumentation comes for the engine control unit which is midships.

The only electrical problems I have ever had were down to earthing (or lack of it in a plastic boat). If you have any screened cables make sure that the screen is connected to chassis ground at one end of the cable only and make that connection as close the to the battery -ve as possible.

Happy sea riding :-)