It is a code of conduct developed and monitored by Renewable Energy Assurance Limited, setting out good practice, which suppliers should follow when selling renewable energy systems.

Suppliers registered under the Microgeneration Certification Scheme must follow the REAL Code (or an equivalent). Because the MCS is a pre-requisite for systems up to 50kW_e, or 45kW_th under the Renewable Heat Incentive, suppliers of such systems should be registered under the REAL Code.