Protection concepts NEC and CEC

The tables below list the types of protection methods and basic concepts of protection according to US and Canadian standards for electrical equipment that is to be operated or installed in hazardous areas. The matrix is constructed to enable the fast cross referencing of protection concepts for classes and divisions, or classes and zones including the applicable US and Canadian standards.
For definitions of divisions and zones, please see the E2S guide to hazardous areas as defined by IECEx, ATEX, NEC and CEC standards and directives.
A similar matrix of protection concepts can also be found for the IECEx and ATEX standards here.

Electrical equipment for flammable gases, vapours and mist
US code	CAN code	Type of protection	Basic concept of protection	Class I Div		Class I Zone			US Standard	CA Standard
				1	2	0	1	2
AEx e	Ex e	Increased safety	No arcs, sparks or hot surfaces				•	•	ISA 60079-7	CSA E60079-7
(NI)	(NI)	Non-incendive				•			ISA 12.12.01 / FM 3611	C22.2 No. 213
AEx nA	Ex nA	Non-sparking			•				ISA 60079-15	CSA E60079-15
(XP)	(XP)	Explosion proof	Contain the explosion and extinguish the flame	•	•				UL 1203 / FM 3615	C22.2 No. 30
AEx d	Ex d	Flame proof					•	•	ISA 60079-1 / UL 1203 / FM 3615	CSA 60079-1
AEx q	Ex q	Powder filled					•	•	ISA 60079-5	CSA E60079-5
AEx nC	Ex nC	Enclosed break						•	ISA 60079-15	CSA E60079-15
(IS)	(IS)	Intrinsic safety	Limit energy of sparks and surface temperature	•	•				UL 913 / FM 3610	22.3 No. 157
AEx ia	EX ia					•	•	•	ISA 60079-11 / FM 3616	CSA E60079-11
AEx ib	EX ib						•	•	ISA 60079-15	CSA E60079-15
AEx nL	EX nL	Limited energy						•	ISA 60079-15	CSA E60079-11
Type X	Type X	Pressurised	Keep flammable gas out	•	•				NFPA 496 (FM 3620)	NFPA 496
Type Y	Type Y			•	•
Type Z	Type Z				•
AEx px	Ex px						•	•	ISA 60079-2	CSA E60079-2
AEx py	Ex py						•	•
AEx pz	Ex pz							•
AEx nR	Ex nR	Restricted breathing						•	ISA 60079-15	CSA E60079-15
AEx m	Ex m	Encapsulated					•	•	ISA 60079-18	CSA E60079-18
AEx ma	N/A					•	•	•		N/A
AEx mb							•	•
AEx o	Ex o	Oil immersion					•	•	ISA 60079-6	CSA E60079-6

Electrical equipment for combustible dust
US code	CAN code	Type of protection	Basic concept of protection	Class II Div		C III Div	Class II Zone			US Standard	CA Standard
				1	2	0	20	21	22
(DIP)	(DIP)	Dust ignition protection	Keep combustible dust out	•	•	•				UL 1203 / FM 3616	CSA C22.2 No. 25
(NI)	(NI)	Dust protected			•	•				ISA 12.12.01 / FM 3611	CSA C22.2 No. 25
AEx ta	Ex ta	Protection by enclosure					•	•	•	ISA 60079-31	CSA C22.2 No. 60079-31
AEx tb	Ex tb							•	•
AEx tc	Ex tc								•
N/A	N/A	Fibre & flying protection				•				UL 1203 / ISA 12.12.01	CSA C22.2 No. 25
AEx maD	N/A	Encapsulation					•	•	•	ISA 60079-18	N/A
AEx mbD								•	•
(PX)	(PX)	Pressurisation		•	•	•				NFPA 496 (FM 3620)	NFPA 496
(PY)	(PY)			•	•	•
(PZ)	(PZ)				•	•
AEx pD	N/A						•			ISA 61241-2	N/A
(IS)	(IS)	Intrinsic safety	Limit energy of sparks and surface temperature	•	•	•				UL 913 / FM 3610	CSA C22.2 No. 157
AEx iaD	N/A						•	•	•	ISA 60079-11	N/A
AEx ibD								•	•