Category Hazardous Area
Intrinsically Safe (IS)
What's the difference between Ex [ia] & [Ex ia] in term of hardware?
The square bracket [] indicates the equipment is "associated apparatus". It doesn't give any indicate where it should be installed. It sometimes used together with other method of protection. For example Ex d [ia] means the equipment/device can be installed in Zone 1, and the containing equipment/circuit inside is suitable for Ex i apparatus in zone 0.
[Ex ia] and Ex [ia] is the same. Normally vendor use [Ex ia]. Common thing we can see this is on the barrier. It only can be used in safe area (e.g control room) but can provide Ex i protection to the device it supplies to.
Explosion Proof (Ex d)
