Isolation Transformer on Fuel Supply Pump Circuits

Some of these standards may be of use to you: http://standards.globalspec.com/search/standards?query=Isolation+Transformers&newSearch=new

Where in the world are you and what country do you plan on using an isolation transformer? Check the local codes and standards at the point of utse

Why would you think they are necessary?

If you are within the US jurisdiction, your application is regulated by the National Fire Protection Agency (NFPA) under the 2014-National Electrical Code (NEC) which is the governing code for electrical installations in the USA. Your application, in particular, is described under the NEC's Art. 450 (Transformers) and Art. 500 (Hazardous Locations) for all Explosion Proof & Hazardous Locations classifications (Class I, II & II) applications. I suggest you get hold of the 2014 edition of the NEC and refer to it for regulatory guidelines towards solving your problem. Probably, you won't need an isolation transformer for this particular use since these type of transformers are used to control the hazardous voltages which might represent a health hazard issue in hospital patients and operating rooms. They are almost always used where you want to isolate the utility power grounding and hazardous currents from a secondary application source. The last time I specified Isolation Transformers was for an operating room in a hospital application which is also regulated by the NEC and the main supplier for these type of transformers was 'Square-D'. hey should also have some information regarding this issue or the indicated utilization. I did an Airport Gas Fueling Station design some years ago and I don't remember using isolation transformers at all. Then again, this was an outdoor open air installation (i don't know what type of installation you are doing) and might not have a need for this type of isolation requirements. One thing is certain, and that is, that any explosion proof installations applications, under the US laws, are strictly regulated by the NFPA under the NEC code.