Wire gauge decision when combining negs

[hzcruiser]

Originally Posted by JRM

Just to pile on...

Ancor makes 14/3 and 16/3 "bilge pump cable" which is basically a triplex tinned stranded cable with a petroleum resistant sheath. Kills all the birds with one stone and is terribly handy for dealing with auto/manual/off bilge pump setups with float switches. Why re-invent the wheel?

So what? Only because they're calling it bilge pump cable doesn't mean it works for all setups. They also sell this very cable in rolls of up to 500ft! So based on your view, I could use this cable to run a bilge pump 500feet away, no worries at all?

It ain't that easy, mate!

[JRM]

Originally Posted by hzcruiser

So what? Only because they're calling it bilge pump cable doesn't mean it works for all setups. They also sell this very cable in rolls of up to 500ft! So based on your view, I could use this cable to run a bilge pump 500feet away, no worries at all?

It ain't that easy, mate!

Sometimes it is. Sometimes "best practices" actually are. Sometimes things seem overly complicated because they are new to us or we are learning. I know I always am.

Thanks for the chuckle. It's been a long "work trip" and that kind of humor is just what I needed. I guess the only thing I can say is, "I can buy eggs in packs of 18, but that doesn't mean I advocate for eating an 18 egg omelette in a single sitting."

Best of luck to you and I hope you find the advice you're willing to accept.

[Bowdrie]

Get those Bosch relays, (black cubes,) and use the helm switches to energize them.
Eliminate runs to helm switches from carrying pump loads.
Can also use the relays to eliminate the float switches from pump loads.
In an ideal world we would like to see pump motors at ~1% voltage drop.

[mcarthur]

I did think about relays, since I'm trying to learn from others and crawl over the shoulders of greats.
There's certainly some who hate the idea (various reasons) and those who accept the problems.
For others looking at this, I've found a few useful discussions (which have confused me not a little ):
- this one - pluses and minuses, and the importance of choosing particular mosfet AND diode choice and placement if you go with relays.
- here - some points about using relays for low-amp switches, as well as manual switching; again some cons, some pros

[team karst]

I like the idea of relays; my reservation is the use of 1/4” flag terminals with currents exceeding 10 Amps. Even if the relay is rated at 30 Amps. More trouble on boats than cars. There is a complication of fusing the control circuit as well as the load.