Rayleigh instruments ri 7x series single phase mid certified meters rayleigh instruments ri 78 80 c the rayleigh instruments ri 78 80 c is a mid approved and certified single phase network kilowatt hour active energy meter it is housed in a 4 module 78mm wide din rail mounting case it can be directly connected up to 80 amps and has modbus rs485 and pulse outputs 1600 impulses kwh as standardthe use of mid certified electricity meters has been made mandatory on private electrical