i hope you doing well.
My question is: if we use an (EX ia) transmitter, is it mandatory that we use barriers or not?
and if we do not use a barrier what happens?
The transmitter will be in the hazardous area compatible with the transmitter specification. A barrier compatible with the transmitter must be installed in the safe area. The barrier limits voltage and current or power to the transmitter and wiring. The capacitance and induction on the circuit must be considered also to keep from storing to much energy in the circuit.
Most modern transmitters are certified as IS, explosion proof and general purpose NEMA 4.
If the transmitter is in a classified area you must use barriers to make the field loop safe or wire it as explosion proof.
It will function without barriers but is not safe, you are breaking safety regulations. If there is a fire, explosion, injury or death, you and your company will be criminally and financially responsible.
If the transmitter is in a non-classified area wire it up without barriers.