At the change over to the new millennium an important conversion will be implemented in the electrical industry and trade. The Pg-( heavy-gauge conduit thread) system which has been in use in Germany for many decades will be converted to the internationally common metric system. 

The conversion of cable glands,conduit systems and enclosures is based on the international metric dimensions standard DIN EN 60423. The heavy-gauge conduit thread range from Pg 7 to Pg 48 will be replaced by the metric range M 12 to M 63.

The European standard for product safety 
DIN EN 50262 (VDE 0619/April 99) exclusively stipulates safety requirements. Dimensions such as the width across corners or the opening of the spanner are not stipulated here.

A major advantage for users in electrical industry and electrical wohlesalers is that 10 Pg sizes are replaced by 8 metric sizes. Therefore a new assignment of the sealing ranges to the rated sizes of the cable glands must be made (figure 1).

Of course metric cable glands only fit with metric openings in the enclosures. If an enclosure or cabinet is equipped with Pg-cable entries, the corresponding cables glands will continue to be available as spare parts.

Cable entries
of enclosures, distribution boards, switching cabinets, service boxes and terminal boxes are changed from Pg size heavy-gauge conduit threads to metric threads by the manufacturers. Here the number of openings in the enclosure may also change with the existing dimensions of the enclosure.

Manufacturers of enclosures and cabinets with integrated equipment have tried to keep the possibilities of entering cables in relation to the electrical function.

Enclosures with fixed hole patterns ensure that cable glands can be arranged close together independent of the manufacturer. For distances between hole centres, please, refer to the documentation of the manufacturer.

Of course enclosures, cabinets and boxes with metric openings only fit metric cable glands, other cable entries and conduits. Pg- cable glands and -cable entries will further be available as spare parts for enclosures, cabinets and boxes with Pg openings wich already are installed.

The product safety standard
is the European standard DIN EN 50086 (VDE 0605/February 99).

The external diameters of rigid and flexible conduits and associated accessories (conduit bends, fixing material etc.) now comply with the system dimensions of the above-mentioned dimension standard DIN EN 60423. This facilitates identification considerably: In most cases the type designation clearly defines the external diameter in mm (example: M16 means an external diameter of 16 mm) (Figure 2).

Note: Apart from the new dimensions, please note the new designations for characteristics of use.

External diameters of Pg heavy-gauge conduit threads compared with metric threads

Even at a later point of time necessary spare parts will be available with Pg- threads, e.g. cable glands, other cable entries and conduits. Therefore there is no need to schedule specific stocks.

What do you have to know about type designation?
In order to keep it simple: Many enclosures will keep their type designation and will additionally be marked with an for metric during the transition period.
All other metric systems (cable entries, flanges, conduits etc.) will receive new type designations.

For more information pease contact:
ZVEI
Zentralverband Elektrotechnik-
und Elektronikindustrie e. V.
Stresemannallee 19, 60596 Frankfurt am Main
Phone:  0 69/63 02-4 51 
Fax:      0 69/63 02-3 83
Mail:      instgeraete@zvei.org
http//www.zvei.de