Like 67dart273 said, by feeding the splice with 2 wires each wire only has to carry 1/2 of the current. The bulkhead connectors also only carry 1/2 the current that way too.
No real reason the bypass the ammeter.
Unless you have massive accessories attached to the stock wiring or it is defective and a super wizbang alternator
1/2 the current to the splice will go on one wire the other 1/2 will go through the ammeter on the other wire.
