FF wrote:
On the one hand, we have a $100 added-feature light soldered into an expensive marine power panel that usually only indicates one failure mode. On the other hand, we have an $8 gadget carried by every residential electrician in North America that actually gives better information on more failure modes than the panel light does.
Yup,
Making 50 million of something in China is always cheaper than hand assembling one of anything anywhere.
*
It's not a "$100.00 added in feature", it's part of any modern marine electrical panel.* It is not possible to put a specific cost on this feature.
As far as it's purpose, it's been said several different ways, but the bottom line is, there is a problem with the power source (dock power or portable generator) that needs to be corrected immediately.* Disconnect the boat from the source untill the problem is corrected.