Home improvements: is my shower safe
The most critical location is directly above the bath, and is designated Zone 1, so any electrical appliance sited in this area plastic trunking needs to have an appropriate IP (Ingress Protection) safety rating. Fortunately, any electric shower sold in Britain will have this rating, and will therefore be safe.
Surface-mounted cabling might look plastic duct untidy, but providing it has been installed correctly it is also permitted under the electrical plastic trunking safety regulations. The “conduit” you mention is more likely to be square plastic trunking, with a push-fit front cover. You might want to prise this off and check that it contains a continuous length plastic duct of cable with no joins, and that the geometry of the trunking does not allow the possibility of water collecting anywhere within it.
By far the most important factor, however, is to check that the shower circuit is protected by an RCD (residual current device) at the consumer plastic channels unit. This should be clear from the labelling of the MCBs (miniature circuit breakers), but if in doubt, you could flick off the RCD switch itself, and check that this has, in fact, cut off the plastic channels supply to the shower.
