Where will the current will flow if there is a fault? That is the question.
There are two things involved here - wiring the radio negative directly to the battery or wiring it to the vehicle chassis. It does make a difference because of the way most vehicle batteries are tied on the negative terminal. If one wires both positive and negative directly to the battery, the negative should be fused to protect the RADIO in case of a fault between the battery and the engine block. It is not a safety issue. Note carefully that the battery negative is wired both to the engine block and to the chassis by direct wires from the battery negative. If the battery were tied only to the engine block and then the chassis were also tied to the engine block (as was pointed out in the case of the boat), the failure mode would not exist. And it is all because the radio is grounded to the chassis through the antenna connection in addition to the negative lead. If both these grounds go to the chassis instead of the battery negative, the problem solved by the fuse in the negative lead would not exist. If the radio negative is connected to the vehicle chassis, the problem does not exist and the negative lead should NOT be fused. 73, Don W3FPR On 4/2/2011 9:40 AM, David Ferrington, M0XDF wrote: > I'm not positive (forgive the pun), but I think ideas have changed on that in > the UK and you again don't fuse the -ve lead, but I'll need to check. > 73 de M0XDF, K3 #174, P3 #108 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
