We make process heaters and sometimes, those are electric immersion heaters. NFPA 70b, 425.22(B) states a 48 amp limit per circuit. However NFPA 87 (which we follow for all of our other heaters) 8.17.1.4 says resistance heaters DON'T have to be subdivided into circuits of 48 amps or less. How can we decide which code to follow? We seem to be… Show more

Our state has not adopted the 2017 NEC yet. That will not happen until late 2020. However, it appears that the 2017 does require it for the products you manufacture. The general rule is that if there are two standards in force for a given item, the more restrictive standard takes precedent. Since you probably market products in more than a single…