Selecting the Right Transformer


Thread Starter


The client has installed unclassified transformer in Unclassified area offshore. The platform is 30 years old. The recent HAC study suggested blanket classification of minimum Zone -2, and now they wish to upgrade this transformer.

Which type of transformer do we need for Zone -2 and where are they available and who is the supplier?

What about the placing this transformer in enclosure??
Kunal, typically standard transformers are allowed in Class I, Div 2 locations provided their accessories are certified for use in Div 2 locations. Following are some of the more salient considerations depending on cooling media:


o Enclosure must be non-ventilated.

o Multiple-strand primary and secondary conuctors, high temperature (class H) insulation.

o Full-Load temp-rise should not exceed 115 degC.

o Core and Coil should be vacuum pressure impregnated.


o They should be installed outdoors.

o All copper conductors are preferred.

o If aluminum, terminations should be carefuly addressed.

o Spill containment.

o Fire-fighting apparatus.

I believe that your reference to Class 2 locations is in error.

Phil Corso (cepsicon[at]aol[dot]com)