Levels of Protection

Encapsulated equipment may be manufactured with EPL ‘ma’, mb’ or ‘mc’.

‘ma’ – must not be capable of causing ignition:

• In normal operation and installation conditions
• Any specified abnormal conditions
• In defined failure conditions

‘mb’ – must not be capable of causing ignition:

• In normal operation and installation conditions;
• In defined failure conditions

‘mc’ – must not be capable of causing ignition:

• During normal operation and installation conditions

Level of protection ‘ma’ #

• Has the highest integrity of protection.
• Remain safe with two internal countable faults.
• The working voltage at any point in the circuit shall not exceed 1 kV.
• May be used in areas requiring EPL ‘Ga’, ‘Gb’ and ‘Gc’ or Category 1,2 and 3.

Level of protection ‘mb’ #

• Remain safe with one internal countable faults.
• May be used in areas requiring EPL ‘Gb’ and ‘Gc’ or Category 2 and 3.

Level of protection ‘mc’ #

• May only used in areas requiring EPL ‘Gc’ or Category 3.