I have an application that falls under NEC427.22, electric heat tracing of pipelines and vessels. 10 branch circuits fed out of an enclosure each have thermal magnetic breaker and GFP 30mA. The problem is that some of the circuits are tripping. Installation has been checked. The GFP breakers are available in 300mA sensitivity and I am considering replacing the 30mA protectors with 300mA. Per NEC427.22, the protector 'is sensitive to leakage currents in the magnitude of 6mA to 50mA'. Does the 300mA GFP comply with 427.22, if not what is the 300mA sensitivity unit used for? Thank you.