Bathroom electrical installation

From Electrical Installation Guide

Bathrooms and shower rooms are areas of high risk, because of the very low resistance of the human body when wet or immersed in water.

Precaution to be taken are therefore correspondingly rigorous, and the regulations are more severe than those for most other locations.

The relevant international standard is IEC 60364-7-701, applicable to the electrical installations in locations containing a fixed bath (bath tub) or shower and to the surrounding zones. Refer to country specific standards (or deviations from the IEC requirements) whenever they exist.

Precautions to observe are based on three aspects:

  • The definition of zones, numbered 0, 1 and 2 in which the placement (or exclusion) of any electrical device is strictly limited or forbidden and, where permitted, the electrical and mechanical protection is prescribed
  • The strict adherence to the requirements prescribed for each zone
  • The establishment of an equipotential bond between all exposed and extraneous metal parts in the zones concerned.

Classification of zones

Sub-clause 701.30 of IEC 60364-7-701 defines the zones 0, 1 and 2, illustrated by the following figures for most common examples.

Refer to the standard for a more complete view.

Fig. Q15 – Definition of zones 0, 1 and 2 (global view)
Fig. Q16 – Definition of zones 0, 1, and 2 – Bath tub complementary examples
Fig. Q17 – Definition of zones 0, 1, and 2 - shower without basin complementary examples

Requirements prescribed for each zone

The IEC 60364-7-701 provides the specific requirements for the different zones defined in classification of zones, applicable to the equipments, circuits ...

It is an international standard that has been achieved as a compromise between countries, considering their existing national standards and regulations, thus it includes a significant number of notes providing country specific requirements. It is thus difficult to share a simplified view of these requirements.

Therefore, what you see below is an overview of the requirements for each zone, based on French standard (NFC 15-100). Always refer to your national standards for the applicable local requirements.

Fig. Q18 – Equipment IP required for each zone
Zone Equipment IP required
Zone 0 IPX7
Zone 1 IPX4[a]
Zone 2 IPX4
  1. ^ IPX5 for showers with horizontal water jets
Cells with a grey background indicate that such equipment is forbidden in this zone.
[a] IPX5 for showers with horizontal water jets
[b] Separation transformer of the circuit shall be installed outside zones 0..2
[c] Outside zones 0..2, all circuits shall be protected by 30mA RCDs (or separation transformer, SELV or PELV)
Fig. Q19 – Overview of the specific requirements for bathrooms and shower rooms (based on French NFC 15-100 standard) - refer to your local standard for actual and complete requirements

Equipotential bonding

see Fig. Q20

Fig. Q20 – Supplementary equipotential bonding in a bathroom