Bonding wire sizing Q

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vas

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good afternoon and a few more Q from me!

ripped all the bonding wires off MiToS (don't want to discuss their condition and securing...) and since I'm finishing cleaning the lazarette and e/r bilges I'm trying to figure out what bonding wires I should use.
I've done my studying (as always) and I'm slightly confused (again as always...)

now then, I'm going to bond all the metal underneath which is:

Z. engine (it's the longest from the anode at 4m routed)
A. stuffing box (? was bonded, do I need to though ?)
B. P bracket (1.5m to anode)
C. rudder (.5m to anode)
D. Anode (1kg thing on the transom)

NOTE:
All the above are times 2 as there's two engines to cater for
Note all skin fittings are GRP (Truedesign NZ) so no bonding on them and depth traducer is also plastic. No need to go through the wood == bronze fittings, as cold formed ply is quite stable and wont create any issues (IIRC BB also agrees on that)
Trim tabs do have 2 anodes each but are not bonded anywhere


Q1. Do I run one cable from each of the Z, A, B, C to the Anode, or do I daisy chain one from Z to A to B to C to D???

Q2. I guess it's good practice to join the two anodes together (they are half a metre apart)

Q3. What gauge wire do I use? From looking at the old ones and visually I'd say I'd be happy with AWG 5 or min 7 (in mm2 terms 16mm2 or least 10mm2 )

Q4. Type of wire to use:
option A. marine rated tined wire green colour (a hell of job trying to find it here!)
option B. pure solid copper wire (at least AWG5 in this case!) and yes it will be a bit tricky to route and i'll need to make sure I have springy loops to cater for vibrations and general movements.

what does the panel say?


cheers

V.
 
See MG Duffs website for general advice. http://www.mgduff.co.uk/

They recommend 4mm² PVC Insulated Multi-Stranded Copper Cable or larger.

I'd aim to make the connections by the shortest route. Separate wiring in the main probably, daisy chain only where appropriate.

Remember that flexible shaft couplings will have to be bridged to complete the circuit to the shafts and props if the anode connections are made to the engine blocks or gear boxes.

Anodes should be reasonably close to and "within line of sight" of the items they are to protect
 
1. I'd be pretty indifferent on daisy chaining vs hub and spoke provided the daisy chaining didn't substantially increased the overall distance (which it generally wouldn't of course). BTW, engine will have internal anodes in the seawater cooling parts
2. Yes
3. 10mm sq is fine. It would be nice to crimp the end terminals. I'd lend you a big crimper if you were local!
4. I wouldn't worry about it being tinned if tinned is hard to find. You'll get many years from untinned, assuming good checks and maintenance bla bla
 
VicS said:
See MG Duffs website for general advice. http://www.mgduff.co.uk/

They recommend 4mm² PVC Insulated Multi-Stranded Copper Cable or larger.

I'd aim to make the connections by the shortest route. Separate wiring in the main probably, daisy chain only where appropriate.

Remember that flexible shaft couplings will have to be bridged to complete the circuit to the shafts and props if the anode connections are made to the engine blocks or gear boxes.

Anodes should be reasonably close to and "within line of sight" of the items they are to protect
Click to expand...

thanks Vics,

will do my extra reading at night as I'm off to do my evening session right now. Looks I could go down at least one size on the cable!

However, this "line of sight" comment worries me as anodes are in the transom around 200mm above the hull-transom edge, so not quite right for P-brackets.
I'm pretty sure I've NOT got flexible shaft couplings. I also do have some reasonable sized anodes on the shafts.

FWIW, with the crappy bonding that was installed, all anodes were evenly worn, no carroty colours anywhere, so must have sort of being working...

cheers

V.
 
jfm said:
1. I'd be pretty indifferent on daisy chaining vs hub and spoke provided the daisy chaining didn't substantially increased the overall distance (which it generally wouldn't of course). BTW, engine will have internal anodes in the seawater cooling parts
2. Yes
3. 10mm sq is fine. It would be nice to crimp the end terminals. I'd lend you a big crimper if you were local!
4. I wouldn't worry about it being tinned if tinned is hard to find. You'll get many years from untinned, assuming good checks and maintenance bla bla
Click to expand...

sorry J, replied to Vics, while you were replying as well..

considering that all bits to be connected are effectively in a straight line, daisy chaining will be much sorter. I may opt for a combo of daisy P-bracket and rudder and a straight one to the engine block.
True 3 anodes per engine

OK, 10mm2 it is. Main problem is that not only I cannot find tinned cable, I cannot even find GREEN cable at that size :( Not happy getting a black one tbh.

will search a bit more then!

cheers

V.
 
Daisy chain is perfectly fine if the items are in a line and if you are careful to make good joints

In my book it would be fine to use black cable and just put a 20mm long band of green heat shrink on, every 300mm or so. Indeed green insulating tape will surely last 10 years
 
When you daisy chain it all up get your multi meter out and do a resistance test between anode and each thing you want to protect, as said above aim for less than 0.3ohms for effective protection.
 
thanks guys,

I'll borrow a crimping tool and do a proper job at getting them all together.

I'll probably order tinned cable. It's a light green/greyish colour so I'll keep it like that.


burgundyben said:
1Kg doesn't sound enough, you can calulate the weight needed on the galvatest website.


http://www.galvatest.com/quickcalc_anodes.html
Click to expand...

nice tool BB, thanks!

didn't like what it came up with though!
says 15kg for my size :eek:

I'll weigh all anodes and sum it all up. Thinking about it, probably I was been silly with estimating each main anode at 1kg... Must be more but not THAT much!
I mean not only the two transom ones, but the small rudder ones and the fist size shaft ones. Wont count the non-bonded trim tabs anodes though.

will report tomorrow on sizes (and Ohm measurements by the w/e

cheers

V.
 
Plus one for tinned copper cable especially in the bottom of the bilge or anywhere wet.

Insulated copper cable lasts 5 minutes when wet with sea water.
 
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