> There is a clever plastic tongue inside that covers both holes and > can > only be shifted if both prongs go in at the same time. Sometimes it > is > acuated by the body (laterally). Some sockets here have shutter on phase and neutral (live and return) which are opened by the longer earth pin being inserted first. RM -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist