MainlySteam
New member
Re: Stu & Vic, What do you use?
I guess I am conditioned by two matters:
- one is I expect good wiring practices (what were the cables doing in a position where engine movement could chafe them, especially with an engine which I assume cannot have been a DC isolated one).
- the other is that I regard fusing the cranking battery as something like putting a weak link in ones anchor chain. Compared with the almost negligible risk in a correctly wired boat of an event where the fuse will protect, the fuse is something one may live to regret one day unless you have alternative standby cranking battery capacity (which by the way, ABYC requires). A fuse is unlikely to protect against general arcing type problems which cause probably 99.9% of fires associated with cranking circuits, but its installation diminishes the reliability of the cranking circuit which introduces another safety matter.
In case of any misunderstanding, I am not against protection. As an example, in a similar case (using the cranking battery and a converted cranking motor) we have a breaker in our windlass supply, however the duty means that the breaker can be rated low as nuisance breaks are just that, a nuisance, and the cable runs are long and so more exposed to damage. But even with a low rating (150 amps in our case) that protection would not, in my view, protect against most risks in the circuit that may lead to fire (importantly it does protect the windlass drive from overload which is not an issue when cranking an engine however).
In the end it is a matter of opinion but people should make their own minds up on it by properly considering what the real risks are (both the electrical safety ones without, and operational safety ones with) and if their concern is the quality of their wiring installation then consider that the fuse will not protect against most arcing events that poor cabling may lead to. One should also consider that if protecting, any method which introduces more terminations in the cabling (ie if a direct battery post fitting is not used) is adding to the risk of arcing type events.
Thanks for the feedback on the case you recounted, and which will be squirreled away among the cases to be remembered.
John
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I guess I am conditioned by two matters:
- one is I expect good wiring practices (what were the cables doing in a position where engine movement could chafe them, especially with an engine which I assume cannot have been a DC isolated one).
- the other is that I regard fusing the cranking battery as something like putting a weak link in ones anchor chain. Compared with the almost negligible risk in a correctly wired boat of an event where the fuse will protect, the fuse is something one may live to regret one day unless you have alternative standby cranking battery capacity (which by the way, ABYC requires). A fuse is unlikely to protect against general arcing type problems which cause probably 99.9% of fires associated with cranking circuits, but its installation diminishes the reliability of the cranking circuit which introduces another safety matter.
In case of any misunderstanding, I am not against protection. As an example, in a similar case (using the cranking battery and a converted cranking motor) we have a breaker in our windlass supply, however the duty means that the breaker can be rated low as nuisance breaks are just that, a nuisance, and the cable runs are long and so more exposed to damage. But even with a low rating (150 amps in our case) that protection would not, in my view, protect against most risks in the circuit that may lead to fire (importantly it does protect the windlass drive from overload which is not an issue when cranking an engine however).
In the end it is a matter of opinion but people should make their own minds up on it by properly considering what the real risks are (both the electrical safety ones without, and operational safety ones with) and if their concern is the quality of their wiring installation then consider that the fuse will not protect against most arcing events that poor cabling may lead to. One should also consider that if protecting, any method which introduces more terminations in the cabling (ie if a direct battery post fitting is not used) is adding to the risk of arcing type events.
Thanks for the feedback on the case you recounted, and which will be squirreled away among the cases to be remembered.
John
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