Engine Bay fuse box

[robtheplod]

Hi All

 

As part of my engine bay tidy up I'm hoping to get rid of the sparrows nest that is those trailing fuse holders going to the battery terminals for the bilge/webasto/Merlin monitor etc and put in a fuse box so fault finding becomes much easier.

 

This seemed good : Fuse Box With Common Power & Ground Buses 12-Way | 12 Volt Planet

 

My query is the connection from this to the battery - does it need to be fused?  The fusebox is 100a total so I'm thinking a 100a fused connection (on 16mm2 cable)?  necessary or not? 

 

thanks!!

rob

 

Edited April 12, 2022 by robtheplod

[Tony Brooks]

Ideally all feeds from the battery should be fused as close to the battery as reasonably possible but outside the battery case but many older boats do not have such fuses. If your new fuse box is located close to the batteries and the positive feed wire is well protected and stands little chance of shorting I would not see having a fuse in the positive feed as being an issue, however I have no idea what the RCD/RCR says about it if it applies to your boat.

[robtheplod]

Thanks Tony, I intend to put the fuse box on mounted board immediately above the batteries (in the green area you see above the batteries in the photo), so the cable run will only be 2 or 3 feet max.

[Alan de Enfield]

15 minutes ago, Tony Brooks said:

RCD/RCR says about it....................

 

 

8.1 A manually reset trip-free circuit-breaker, or a fuse, shall be installed within 200 mm of the source of power for each circuit or conductor of the system or, if impractical, each conductor shall be contained within a protective covering, such as a sheathing conduit or cable trunking, for its entire length from the source of power to the circuit breaker or fuse. The following constitute exceptions.

 

a) The main power-feed circuit from the battery to an engine-cranking motor, if sheathed or supported to protect against abrasion and contact with conductive surfaces. 

b) The main power-feed from the battery to the panel-board (switchboard), distribution panel or fuse block, if sheathed or supported to protect against abrasion and contact with conductive surfaces. See 7.2.**

 

If the fuse or circuit-breaker at the source of the supply conductor is sized to protect the smallest conductor in the circuit, only the fuse or circuit-breaker at the source is required

 

** 7.2 Conductors that are not sheathed shall be supported throughout their length in conduits, cable trunking, or trays, or by individual supports at maximum intervals of 300 mm

[robtheplod]

29 minutes ago, Alan de Enfield said:

 

 

8.1 A manually reset trip-free circuit-breaker, or a fuse, shall be installed within 200 mm of the source of power for each circuit or conductor of the system or, if impractical, each conductor shall be contained within a protective covering, such as a sheathing conduit or cable trunking, for its entire length from the source of power to the circuit breaker or fuse. The following constitute exceptions.

 

a) The main power-feed circuit from the battery to an engine-cranking motor, if sheathed or supported to protect against abrasion and contact with conductive surfaces. 

b) The main power-feed from the battery to the panel-board (switchboard), distribution panel or fuse block, if sheathed or supported to protect against abrasion and contact with conductive surfaces. See 7.2.**

 

If the fuse or circuit-breaker at the source of the supply conductor is sized to protect the smallest conductor in the circuit, only the fuse or circuit-breaker at the source is required

 

** 7.2 Conductors that are not sheathed shall be supported throughout their length in conduits, cable trunking, or trays, or by individual supports at maximum intervals of 300 mm

Thanks Alan, so i read that yes i do need to fuse!  

[ditchcrawler]

15 minutes ago, robtheplod said:

Thanks Alan, so i read that yes i do need to fuse!  

Or conduit 

[David Mack]

17 minutes ago, ditchcrawler said:

Or conduit 

Or simply support the cable between batteries and fuse box every 300mm.

[Alan de Enfield]

59 minutes ago, robtheplod said:

Thanks Alan, so i read that yes i do need to fuse!  

 

I'd suggest that fusing is a simple method of achieving what you need to do, or you can 2) 'conduit' each cable to your main RCD / Fuse box / circuit breakers, or 3)  clip each cable every 300mm to the RCD / fuse box / circuit breaker.

 

Options 2 and 3 are (I believe) to reduce the chance of movement &/or vibration resulting in chafing of the insulation potentially causing a short.

[cuthound]

2 hours ago, robtheplod said:

Hi All

 

As part of my engine bay tidy up I'm hoping to get rid of the sparrows nest that is those trailing fuse holders going to the battery terminals for the bilge/webasto/Merlin monitor etc and put in a fuse box so fault finding becomes much easier.

 

This seemed good : Fuse Box With Common Power & Ground Buses 12-Way | 12 Volt Planet

 

My query is the connection from this to the battery - does it need to be fused?  The fusebox is 100a total so I'm thinking a 100a fused connection (on 16mm2 cable)?  necessary or not? 

 

thanks!!

rob

 

 

You are aware that you mustn't disturb bird nests between the beginning of March and the end of August aren't you? 😂😅

[Alan de Enfield]

7 minutes ago, cuthound said:

 

You are aware that you mustn't disturb bird nests between the beginning of March and the end of August aren't you? 😂😅

 

But if you put it on ebay, or the London Boaters facebook page you'll sell it easily, all those CMers are desperate to buy all the nests they can so as to avoid having to move.

[Tracy D'arth]

Remember, maximum of 4 cables on any one terminal.

Why not put a megafuse on each positive battery terminal rated at a suitable amperage, say 200A? But you will still have to fuse the thin cables at the correct rating.

[PaulD]

2 hours ago, Alan de Enfield said:

 

I'd suggest that fusing is a simple method of achieving what you need to do, or you can 2) 'conduit' each cable to your main RCD / Fuse box / circuit breakers, or 3)  clip each cable every 300mm to the RCD / fuse box / circuit breaker.

 

Options 2 and 3 are (I believe) to reduce the chance of movement &/or vibration resulting in chafing of the insulation potentially causing a short.

Fuse is likely to be high capacity. Better in a fuse box than lying on top of the battery bank or hanging in mid air. 

[Alan de Enfield]

8 minutes ago, PaulD said:

Fuse is likely to be high capacity. Better in a fuse box than lying on top of the battery bank or hanging in mid air. 

 

Are you looking to run all the battery cables to a busbar and then a single megafuse from Busbar to 'fuse box / circuit breakers' ? or, run each cable less than 200mm from the battery to a fuse box ?

[ditchcrawler]

I think Gibbo always said that the monitor wire had to go directly to the battery post, not to any other point that may be carrying current. So you will negate that if you take a wire from the battery to the fuse box and then connect the monitor cable there.

[Tony Brooks]

The OP is fitting a 2x positive bus bar with fused outputs plus a negative bus bar so all those cables, when connected to the new fuse box will be fused (hopefully at the correct rating fr the cable or less). The only question is MUST he fuse the cable between battery and new fuse box. The answer depends upon the RCR/RCD status of the boat, the cable run length and how the cable is protected from mechanical damage leading to short circuits. If the boat is pre-1997 then as long a she understands the dangers from a short and mitigates them the answer is no, it is not mandatory. If it is post 1997 then it would be a good idea to fuse the supply cable but he can  avoid that by a shorter cable length or sleaving/trunking etc.

[Alan de Enfield]

1 minute ago, Tony Brooks said:

The OP is fitting a 2x positive bus bar with fused outputs plus a negative bus bar so all those cables, when connected to the new fuse box will be fused (hopefully at the correct rating fr the cable or less). The only question is MUST he fuse the cable between battery and new fuse box. The answer depends upon the RCR/RCD status of the boat, the cable run length and how the cable is protected from mechanical damage leading to short circuits. If the boat is pre-1997 then as long a she understands the dangers from a short and mitigates them the answer is no, it is not mandatory. If it is post 1997 then it would be a good idea to fuse the supply cable but he can  avoid that by a shorter cable length or sleaving/trunking etc.

 

A fair and reasonable summary.

[dmr]

6 hours ago, cuthound said:

 

You are aware that you mustn't disturb bird nests between the beginning of March and the end of August aren't you? 😂😅

 

But what you see is actually known as a rats nest and these do not have protection 😀

[jonathanA]

Does the BSS mandate a suitable cover or terminal covers on batteries? 

[David Mack]

It would be quicker for you to look up the BSS requirements yourself than to wait for replies here which might or might not be correct.

[Alan de Enfield]

36 minutes ago, jonathanA said:

Does the BSS mandate a suitable cover or terminal covers on batteries? 

 

Yes.

[jonathanA]

31 minutes ago, David Mack said:

It would be quicker for you to look up the BSS requirements yourself than to wait for replies here which might or might not be correct.

Thanks for your helpful  (not) and irrelevant response 

 

It was for the ops benefit as there doesn't seem to be evidence of either in his pic or mention of in his posts.

 

I don't care as mine are covered and meet BSS requirements.

Edited April 13, 2022 by jonathanA

[ditchcrawler]

42 minutes ago, Alan de Enfield said:

 

Yes.

I don't think I would call this a mandate

[Alan de Enfield]

5 minutes ago, ditchcrawler said:

I don't think I would call this a mandate

 

 

As it is compulsory requirement it could be said to be a mandate :

 

Mandate : an official order or commission to do something.

 

But I suppose it would be easier just to say "Yes it is a requirement"

[ditchcrawler]

1 minute ago, Alan de Enfield said:

 

 

As it is compulsory requirement it could be said to be a mandate :

 

Mandate : an official order or commission to do something.

 

But I suppose it would be easier just to say "Yes it is a requirement"

I think the question on how it was to be done, not if it had to be done.

[Alan de Enfield]

1 minute ago, ditchcrawler said:

I think the question on how it was to be done, not if it had to be done.

 

 

I must have misunderstood the question :

 

1 hour ago, jonathanA said:

Does the BSS mandate a suitable cover or terminal covers on batteries? 

 

 

I read it as "is a suitable cover, or termial covers required"

 

Maybe the questioner (jonathanA)  could explain if he wanted to know if it was required, or, wanted to know what to do and how to do it ?