Boat master fuse - currently 100A NH00 type

[KompetentKrew]

Hello,

I'd quite like to replace this fuse holder as I suspect that corrosion is causing a bad contact (high resistance?) under load.

As you may infer from the photos, the bare ends of the wire (the largest is maybe 8mm in diameter) are inserted into the ends of the fuse holder, and screws are tightened, which clamp them into place.

I find this is of the NH fuse type and the only replacement holders I can find have a screw on each end, instead of the clamp, which would require ring terminals to be crimped onto the ends of the cables before installation. I would prefer not to do this at this time.

Does anyone have any thoughts on this, please? Could I replace fuse and holder with a different type that would drop in easily without disturbing my electrics too much?

 

[lw395]

Clamping down onto bared wires like that is more 'mains' practice than 'automotive'.
Putting so many wires into one connector is frowned on by many people, and it's often stressful for the electrician as well as the wires.
You might consider using some sort of connector block to common all those wires, then wiring to a fuseholder.
Connector Blocks 100A Single Pole
maybe.
Can't say I like the idea.
You might find hardware in the RS catalogue?
1BS101 | Cooper Bussmann 100A Stud Mount Bolt Down Fuse Block, 600V | RS Components



Anything with 100A loading needs to be done properly as even a small voltage drop is a lot of watts.

The redeeming feature of what you have is that the +ve connections are nicely protected from casual contact, which many installations fall short on.

 

[pvb]

I find this is of the NH fuse type and the only replacement holders I can find have a screw on each end, instead of the clamp, which would require ring terminals to be crimped onto the ends of the cables before installation. I would prefer not to do this at this time.

Does anyone have any thoughts on this, please? Could I replace fuse and holder with a different type that would drop in easily without disturbing my electrics too much?

You can get screw-clamp connectors which fit on the ends of ordinary holders.



Jean Moeller KM2G-F/AF30-40 V90-120 JEAN MOELLER V-STEEL-FRAME CLAMP WITH CONNECTING LUG, MAX RANGE: 25-240MM², FALSE | Kempston Controls

 

[PaulRainbow]

That's a bodge that should be changed.

I suspect the fuse holder originally only had the thickest cables fitted to it and someone has added the thinner ones, which will not be protected by a 100a fuse. The smaller wire coming from the bottom of the holder also has no protection at all.

I would fit something different for the main fuse, using crimped on rings, and fit separate fuses in the smaller cable.

 

[KompetentKrew]

That's a bodge that should be changed. …

I would fit something different for the main fuse, using crimped on rings, and fit separate fuses in the smaller cable.

Yes, it's certainly on my list of things to do, it's just not right at the top of that list.

You can get screw-clamp connectors which fit on the ends of ordinary holders.

View attachment 93241

Jean Moeller KM2G-F/AF30-40 V90-120 JEAN MOELLER V-STEEL-FRAME CLAMP WITH CONNECTING LUG, MAX RANGE: 25-240MM², FALSE | Kempston Controls

Thanks very much! Exactly what I needed.

 

[superheat6k]

The gG fuse is HRC motor rated, so you wil likely be drawing several hundred amps for several seconds before this thing blows. Great for large capacity 3 phase 400vac AC motors, but not sure I would fit one to my 12 VDC system. I have a 6" nail that will offer similar protection !

 

[SiteSurfer]

Factory fitted type of fuse on my 2003 Bav. they do seem a bit overkill

 

[PaulRainbow]

Factory fitted type of fuse on my 2003 Bav. they do seem a bit overkill

It's also a standard fit on Bavs for the windlass. Not a Bav knocking post, but these are totally unsuitable for windlasses, where thermal breakers should be fitted.

 

[SiteSurfer]

Spot on, that’s how mine is wired (now)

 

[pvb]

The gG fuse is HRC motor rated, so you wil likely be drawing several hundred amps for several seconds before this thing blows. Great for large capacity 3 phase 400vac AC motors, but not sure I would fit one to my 12 VDC system. I have a 6" nail that will offer similar protection !

I thought the gG speed rating indicated a fast-acting fuse for general cable protection. The type used for motor protection is usually the aM speed rating, which is slow-acting. My Bavaria has gG rated NH fuses.

NH Fuses Explained