Panel to fused terminal block ??

[Time2Go]

Hi Friends,
We are replacing the main DC panel and have ordered a new panel
with 20 15 amp breakers and 4 20 amp breakers.
The plan is to bring all the positive loads from the panel to
individually fused terminal blocks ( BlueSea 5035)
Negative and Grounds will go to Dual Buss bars (BlueSea 2702)
We did this so that we can

1. Fuse each load circuit exactly as it should be
without having to advance specify the breaker size.

2. Make all connections to the fuse block without ever having to run wires and make connections to and on the panel.

3. Decrease the density and have some room to spread
out the interconnect panels.


Some loads (Windlass, AutoPilot, Fridge, Bilge pump and future
Electric winch) will run directly to positive and negative buss bars
before the panel and will be individually switched,
wired and fused accordingly,

The question is what gauge wire to use from the positive side of the
breaker to the fused terminal strip?
Each breaker will feed one
circuit on the fused terminal block. These will be relatively
low amp loads such as radios, instruments, running/anchor lights,
USB charging ports, gas solenoid, cabin lights and so on.
We had planned on using 14 gauge but am having second thoughts.
Boat is a center console 44' Irwin with the panel in the middle of the boat.
Longest run will be the anchor light, with most being much shorter.
Thanx & Cheers
Neil

[GordMay]

#14 AWG Cu wire will be protected, by the (20) 15A breakers; and #12 AWG Cu wire will be protected, by the (4) 20A breakers.

[cal40john]

Are each of the cabin lights going to be connected to a separate fuse block of the right size? Or are several of them in parallel on one circuit? If you fuse for all the lights in parallel, then you are allowing much greater current to flow than to protect the wires to one bulb/LED. Also do bulbs/LEDs ever cause a fire when they die? (Assuming the wire is appropriately protected with a circuit breaker sized to protect the wire in case of a short.)

Are there other circuits with multiple devices?

Things like radios have fuses builtin to protect the device, so another fuse is redundant.

This is a belt and suspenders idea (redundant) for many of the circuits on the boat.

16 gauge wire is the smallest load carrying wire recommended on boats for mechanical reasons, so you're not saving much in gauge size from 14.

Ampacity of 16 gauge 2 conductor wire is above where your 15 amp circuit breakers trip.

[Frankly]

Might look at upsizing all the breaker feeds to say #10 or 12 (reasonable physical size to handle in that situation). Probably short runs but often voltage drop is the short pole in the tent.

I think your distribution concept has some real merit, but would strongly suggest that you use separate return bus set up (as you indicated). Physical distance between positive and negative is usually a good idea and spreading the wiring out over a large area just makes electrical life easier.

Did not look up the BS part number but do use the ATO blocks. ATO/ATC fuses are just a better mousetrap.

On my 1991 IP did something similar in the spare breakers were run to a back board terminal strip so that you did not have to tear into that wire bundle when adding a circuit.

Good luck I think you are on to something better/ more flexible with minimal additional complexity.


Frankly

[GordMay]

Originally Posted by Frankly

... Did not look up the BS part number but do use the ATO blocks. ATO/ATC fuses are just a better mousetrap...

Indeed.
On ATO/ATC blade fuses, the Amp rating is shown on the top of the plastic body (visible in use), and are also colour coded. So even if the Amp rating number is illegible, you can still determine the fuse rating, by its standardized body colour.
Additionally, they’re available as “Smart Glow” fuses, that feature an indicator light that glows when the fuse is blown, saving time to troubleshoot an open circuit.
➥ https://www.littelfuse.com/~/media/a..._datasheet.pdf

[stormalong]

Seems to me that you are overthinking this and adding more complexity than you need. 24 circuits is probably enough for most boats. Large loads like electric winches should not go through the panel. Individual lights can come off of one circuit without fusing each one. The overload protection is there to protect the wiring from from overheating, not the individual devices. If you are going to fuse each light separately the you will need to run a wire for each light back to the panel.

A little more planning and you could eliminate the fuses altogether. Order the panel with specifically sized breakers or without breakers and order them separately and mount them where you want.

[MarkSF]

Wiring should be sized :

1) Able to take the rated current of the breaker. There are de-ratings for engine space, multiple wires in a bundle, and so on.

2) Less than the allowable voltage drop. For instruments, it is 1%, for other items, 3% is allowable. You will probably end up using thicker than 14 gauge for voltage drop reasons.

There is an excellent calculator at :

https://www.genuinedealz.com/pages/v...rop-calculator

[MarkSF]

Originally Posted by stormalong

A little more planning and you could eliminate the fuses altogether. Order the panel with specifically sized breakers or without breakers and order them separately and mount them where you want.

I've used the Blue Sea Systems fuse blocks, and they are an excellent solution for bunches of items - for example, instruments. All the instruments on my NMEA2000 network are powered up by one breaker, and then wired to the fused terminal block. It makes for a very tidy installation, and devices can have the correct, ie small, fuse size, properly protecting each device.

Having individual fuses for each light, instrument or whatever is an advantage, not a deficit, as the device protection is better, and one faulty device will not trip the breaker for all.

[stormalong]

Originally Posted by MarkSF

I've used the Blue Sea Systems fuse blocks, and they are an excellent solution for bunches of items - for example, instruments. All the instruments on my NMEA2000 network are powered up by one breaker, and then wired to the fused terminal block. It makes for a very tidy installation, and devices can have the correct, ie small, fuse size, properly protecting each device.

Having individual fuses for each light, instrument or whatever is an advantage, not a deficit, as the device protection is better, and one faulty device will not trip the breaker for all.

Well I have to disagree. All of my sailing instruments are on one five amp circuit breaker and in 30 years of ownership I have never had a problem. The same can be said for the lighting circuit. Two breakers, one port and one starboard - never a problem. Then you get down to navigation lights. A circuit breaker for each configuration. Deck lights, steaming light, masthead three different lights, etc. Each individually controlled by an appropriately sized circuit breaker. No need to add fuses. I do, however, have a box of circuit breakers that I have replaced with appropriate sized breakers. A little planning on the OP's part and even that could be reduced. Why make anything more complex than necessary.

[Secondshift]

Originally Posted by MarkSF

Having individual fuses for each light, instrument or whatever is an advantage, not a deficit, as the device protection is better, and one faulty device will not trip the breaker for all.

... And I would have to agree. I have had two failures since we've owned our 33'. Much to be uncovered from who knows how many PO's. Work in progress.

The first of which was the cabin lights (all on one breaker). Though the problem was obvious. I disconnected the last light turned on. This happened at anchor during Hurricane Dorian so it was initially unsettling.

The second of which was a one hour delay tracing down why the running light circuit kept popping. The compass light was branched off in a bundled mass . Somewhere in the wheel pedestal the wire is shorted.

Avoidance of cascading failure and easier diagnoses would have been preferred in both cases.

Best Regards

[Frankly]

The advantage I see is an improvement in flexibility going down the road and circuit selectivity (the ability to clear an electrical problem while leaving everything else functional).

A couple of examples: port and stbd cabin light circuits run to a single breaker. Problem with a light, in the dark. Split the circuit with fuses one side maybe still working. Running lights (bow, stern, compass). Water shorts out the bow light no compass. Instrument breaker feeding Chart Plotter, instruments, radar, autopilot all on individual fuses (one breaker turns it all on). The ideas go on.

Don't have to do all circuit breaker feeds but I find tearing into the back of my panel to change a breaker or add a circuit a real PITA. To have a single laced wire bundle and fixed circuit breakers feeding fuse blocks or terminal strips on the back board an improved approach.


Frankly

[mitiempo]

Originally Posted by stormalong

Well I have to disagree. All of my sailing instruments are on one five amp circuit breaker and in 30 years of ownership I have never had a problem. The same can be said for the lighting circuit. Two breakers, one port and one starboard - never a problem. Then you get down to navigation lights. A circuit breaker for each configuration. Deck lights, steaming light, masthead three different lights, etc. Each individually controlled by an appropriately sized circuit breaker. No need to add fuses. I do, however, have a box of circuit breakers that I have replaced with appropriate sized breakers. A little planning on the OP's part and even that could be reduced. Why make anything more complex than necessary.

I agree. It makes sense to run a feed from a breaker to a fuse block for electronics.

But not for everything else like lights, pumps, etc.

Remember the breaker on the panel - or the fuse you are adding - is only there to protect the wire, not the item at the end - the load.

Every added connection is a possible failure point. The less the better as long as there is protection. The breakers on the panel provide this.

The only situation where your addition of fuse blocks for every load makes sense is if the main panel is only composed of switches, not breakers.

[Time2Go]

Finished panel and fused interconnect
Thanks to all for your comments
Breakers 1-20 are 15 amp
connected to fuse block with 14 gauge
Breakers 21-24 are 20 amp
connected using 12 gauge
Ring terminals are Ancor heat shrink
Ancor Marine wire
Labels are Klein Tools Wire marker
( covered with clear heat shrink tubing)
Panel is Paneltronics
Fuse blocks and Bus bars are Bluesea
Tools used: Stripmaster wire stripper,
Marinehowto DIY Modular crimp-it,
RV Rhodes cable tie gun
Tacklife Mini hot air gun
The main design criteria was that we
never wanted to touch the panel
after install, and locate the interconnect
blocks in a more convenient location.
In a perfect world and with dead on certainty
the fused interconnects could be eliminated
if one knew for sure what would be
connected to each circuit. That is not
our case. This arrangement gives us
100% configurability of circuit protection
just by swapping a fuse.
Total cost of this project was under
one thousand US.
Again many thanks to all who
offered advice, opinions and knowledge
Cheers
Neil

[GordMay]

Nice job, Neil.

[Frankly]

I think that arrangement will give you a lot of flexibility going forward. Hope you can independently switch the back lightning, might keep you awake at night.


Frankly