IEC 60238 Edison screw lampholders

In case of lampholders with metal screw shell and metal outer shell, contact between these parts shall be prevented by an insulating ring which shall not be separable from the live parts or the metal outer shell by hand.
Compliance is checked by inspection.
NOTE The protection by the insulating ring is consildered sufficient if its length is approximately equal to that of tho ecrow choll.

It shall be possible to lock the threaded entry on the conduit. Locking devices can either be part of the lampholder or be provided by the design of a luminaire.
Except for angled lampholders, it shall be possible to operate the locking device from the inside, if provided as part of the lampholder.
If a locking device is provided by the design of a luminaire, its efficiency cannot be checked.when testing the lampholder; such a check shall be made during testing of the luminaire.

NOTE Such lampholders are not intended for retail sale.
This requirement does not apply to lampholders E5 and E10. Compliance is checked by inspection and, for lampholders having an integral locking device,by the test of 16.4.

LISUN following instruments fully meet IEC 60238 Edison screw lampholders: