Circuit Breaker in Mack Truck Battery Lead

[Bat2way]

Maratrac UHF install in late-model Mack front-loading garbage truck. Complaint was radio not working at times. The initial test of this radio's operation was fine, however the customer called the next day with same complaint. A better clue from the customer was that the radio cuts off after transmitting 3 seconds, then it powers back on. After checking this complaint in the truck, it was found the B+ hook-up point marked "Battery" ran through a 20 Amp circuit breaker which caused the trip when transmitting over 3 seconds. A 30+ Amp source was needed so the solution was to tilt the cab and run a B+ wire following the cab harness to a very easily accessed battery connection point on the inside framerail by the engine. Lower powered front-mount radios would never have this problem.

[Tech225]

Why not just use a bigger breaker?

[techie]

Why not just use a bigger breaker?

Probably because the wiring associated with that breaker was sized for 20 amps, and it would be necessary to run new wiring anyway?
You don't want to go around changing breakers without checking to make sure that the associated wiring can handle the additional load.

[Tech225]

I was thinking that, but I wasn't sure if it was a wiring deficiancy or just an overload problem. If he used the harness supplied with the radio, it would have been sufficiant with just the different breaker. Couldn't tell.