surfix in hazardous areas

[bergie]

i have always used surfix for lighting in zoned areas. theres very little chance of damage high up. the inspection authority in kuilsriver accept it. however today another master sparky says its illegal as in hazardous areas the earth wire must be the same size as the live conductors.
any clarification? andy?

[AndyD]

Can you calrify what the zoned areas are ie what Division/Zone? I'm guessing you're meaning Ex?

[AndyD]

From SANS60079

15.3 Apparatus not requiring earthing
Where there is no requirement for earthing or bonding, for example, in some types of
electrical apparatus having double or reinforced insulation, or for which supplementary
earthing is not necessary, an internal or external earthing or bonding facility need not be
provided.
NOTE Double insulated apparatus, while not presenting a risk of electrical shock, may need to be earthed or
bonded to reduce the risk of ignition.
15.4 Size of conductor connection
Earthing or equipotential bonding connection facilities shall allow for the effective connection
of at least one conductor with a cross-sectional area given in Table 5.

[ATTACH=CONFIG]3296[/ATTACH]

In addition, earthing or bonding connection facilities on the outside of electrical apparatus
shall provide effective connection of a conductor with a cross-sectional area of at least
4 mm2.

So if the CSA of your live is <16mmsq then the earth must be the same size. This would rule out all domestic installation cables as the earth is invariably one or two CSA sizes smaller than the live and neutral.

[bergie]

ex zones yes .
mmmm, i also see in sans 10086 ,something about "if the required earth conductor size cannot be achieved,the main circuit must be on an earth fault protection system."
the lights i am doing are on 300 ma earth leakage. all metal equipment are bonded with a 10mm external earth. the lights are plastic of course.