Why do horn and clock attach to the battery?

[Forumadmin]

Since I am re-designing the wiring of the SC, I was wondering if there was any electrical reason why the horn and clock do not go through to the A1 terminal as by doing so they bypass the current draw sensing in the regulator. I know that when the electric fan was so attached, the battery gradually ran dead on a rally because the regulator did not compensate. I subsequently moved the fan to the A1 terminal.
Clearly Jowetts saved money by only fitting two fuses: one to connect equipment when ignition was switched off and the other for when it was switched on.
I am fitting a 16 way fuse box to correctly fuse each wiring circuit rather than expect each wire to carry the 35A of the Jowett fuses. Fire safety!Thus I am proposing to connect the horn and clock and other battery fed ancillaries to the A1 terminal via fuses.
Who agrees this is correct?

A possible reason is that the horns draw so much current (allbeit sporadic) that the regulator coil might be overloaded. Another is that the clock might suffer voltage fluctuation caused by the drop across the regulator current coil. Both arguments I find weak.

The effect of course is that neither device would have shown passing current through the ammeter when engine was switched off. Thus the ammeter itself may have been damaged by the horns. Since the SA has an air horn(for Italian roads) that takes less current than the Jowett horns, I would not have experienced such a problem.

[Drummond Black]

Keith, Are you fitting an Alternator or sticking to the original Dynamo ?

[Forumadmin]

Like the SA I will provision both; but will fit alternator initially. In either case the car will be negative earth.

[vicboddy]

On my SC as found, there was a battery cut off switch. THe clock was wired directly to the battery so that it kept time when the battery was isolated. So were some wierd side lights fitted to the top of the wings, presumably as parking lights. I suspect the answer to your question is linked to a similar battery cut off facility. Regards V

[Forumadmin]

It is sensible to put a fuse in the clock circuit and not connect directly to the battery. Helps if you are not one who disconnects battery when doing anything on the car!