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What are the rules for installing electrical appliances in bathrooms and shower rooms?

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The electrical circuits supplying water to a room must be protected by a 30 mA differential switch. But that is not enough. But this is not enough. Regulatory distances must be respected. 

Summary of the article (5 minutes reading):

  • Which premises are affected by the regulations?
  • Section 701 of BS 7671:2018: 4 volumes to be respected
  • Taking into account the fixed walls of baths and/or showers in the delimitation of volumes
  • What is allowed depending on the equipment, the insulation classes of the devices and the protection ratings (IP)

NF C15-100 standard (for FRANCE): the different volumes of a bathroom or shower (with bathtub, shower or spa)

The NFC 15-100 standard is the reference that regulates low-voltage electrical installations in residential and commercial buildings in France. As part of the protection of the electrical installation and people, the standard defines 4 volumes for bathrooms and showers. Its objective is to define what is authorized in what volume (plug, switch, radiator, heated towel rail, lighting, tumble dryer, etc.). The volumes are defined from the following water points: bathtub, shower (with tray, cabin, dressing room), spa.

Regulatory volumes (NF C 15-100 part 7-701):

  • Volume 0:
    • The volume created by the inside of the bathtub or the shape / height of the shower tray (if there is a shower tray).
    • For walk-in showers, it corresponds to the shape of the 10 cm raised shower tray. The shape is defined by volume 1.
    • The hidden volume corresponds to the space under the bathtub or under the shower tray. It is not included in volume 0 although the security rules are the same.
  • Volume 1:
    • From the outer edges of the bathtub and rising to a height of 225 cm (from the bottom of the bathtub).
    • For showers with a tray, the volume rises from the shower tray to a height of 225 cm or to the height of the shower head, if the latter is above 225 cm.
    • For walk-in showers (without a shower tray), draw a circle with a radius of 1.2 m that will rise 225 cm or the height of the shower head if it is above 225 cm. The starting point of the radius of the circle follows the following rules:
      • in the case of a shower head: the center of the shower head.
      • in the case of the hand shower: the connection point of the hose (at the mixing valve)
      • in the case of a “rain” shower: all points that make up the outer edge of the waterfall
    • For showers with horizontal jets, volume 1 ends on the next wall that blocks the water jet.
    • In the case of multiple sprinklers, we take all the volumes defined by each sprinkler.
  • Volume 2:
    • Volume from 0 to 60 cm around volume 0 and 1, up to a height of 225 cm (same height as volume 1).
  • Outside Volume: the rest of the bath volume.
volumes baignoire et douche nf c 15 100 pour salle de bain

Bathtub and shower volumes with shower tray nf c 15100 for bathroom

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volumes douche italienne électricité salle de bain

The NF C 15-100 standard largely complies with CENELEC’s European standard HD384 and IEC’s international standard 60364.

The equivalent in Europe:

Taking into account the fixed walls of bathtubs and / or showers in the delimitation of the volumes

It is accepted as a rule that volumes may be limited by the presence of fixed walls (interior wall, partition) and perennial (that is, permanent non-removable) adjoining the ground and whose height is greater than or equal to that of the volume in question (for example , more than 2.25 m for volume 2).
The wall material (plaster, plexiglass, glass, plasterboard, etc.) does not influence the notion of “fixed and evergreen” as long as it is firmly fixed to the wall and the floor and contiguous. (without letting the water pass).
Consequently, removable shower screens (sliding or folding), or even shower or bathtub walls that do not extend over the entire height (less than 225 cm) are therefore not factors that totally limit the volume.
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What is authorized according to the equipment, insulation classes and protection indexes.

équipements autorisés en salle de bain selon les volumes - volumes salle bain classe isolation
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The rules that the equipment must respect and the protection index (IP) (always consult a professional for more details):

On volume 0 (IPX7):

  • It is forbidden to install any electrical equipment except for class 3 IPX7 lights powered with SELV (very low voltage) 12 Volts max. alternative
  • the same in the hidden volume
In volume 1 (IPX5):
  • a maximum 12V (alternating current) class 3 SELV (Very Low Voltage) lighting device with transformer, or 30V direct current
  • Degrees of protection authorized: IPX4 or IPX5 (if they are horizontal jets)
  • Class 1 storage water heater installed horizontally (tolerated if placed as high as possible)
  • instantaneous water heater (class 1) if it is powered directly by a cable without a connection box.
  • a pipeline to supply the authorized devices in these volumes.
  • Note: the power supply must be installed outside of volumes 0, 1 or 2
In volume 2 (IPX4):
  • storage water heater (cumulus) (class 1)
  • instant water heater (class 1)
  • Authorized lighting in volume 1 + 230V class 2 lighting protected by differential circuit breaker 30 mA max. The transformer can be installed on the drywall (if this serves as a ceiling). Class 2 lighting.
  • Class 2 electric heater (radiators)
  • razor plugs (with 50VA max isolation transformer)
  • Degrees of protection authorized: IPX4 or IPX5 (if they are horizontal jets)
  • Note: the power supply must be installed outside of volumes 0, 1 or 2
The so-called “outside” volume does not have any special restrictions for electrical appliances.
  • lighting class 1
  • grounded outlet (prohibited on the floor, above a sink)
  • washing machine (class 1), tumble dryer (class 1)
  • Class 1 electric heater (radiators)
  • isolation transformer
  • connection box
The protection index is a characteristic that derives from an international standard that refers to the tightness of equipment (the intrusion of a solid or liquid body).
The different protection indexes for the bathroom:
  • IPX4: projection of water from all directions
  • IPX5: projection against water jets with lance from any direction
  • IPX7: projection against the effects of temporary immersion.
The insulation class is a characteristic that is applied to all electrical devices in order to define their level of insulation and therefore protection for the user. This item appears on the device nameplate. Please contact the manufacturer in case of any doubt.
The different types of insulation:
  • Class 1: grounding for all metal parts of the device (equipotential grounding). The device must have a grounded plug that must be connected. There is no danger for people if the electrical installation of the house works normally (differential circuit breaker, earth).
  • Class 2: double insulation (or reinforced insulation) without ground. This means that the plug of the device does not need a ground wire as the device is double insulated (metal parts are not accessible). There is no danger to humans.
  • Class 3: Class 2 insulation AND very low voltage transformer (SELV galvanic isolation) mandatory. The device works with a very low safety voltage (maximum 50 V in alternating current).
Electrical outlet box placed near sinks or sinks
In this specific case, we can distinguish the room in which the outlet is placed. If it’s a bathroom or vanity, the location of the outlet follows the volume rules outlined earlier in this article. Therefore, the rules are clearly established to define the distance between the shower or bathtub and an electrical outlet. But what about the distance between the outlet and a sink (located in that same bathroom)? The minimum required distance is not clearly specified or imposed by the standard. However, it seems common in construction sites to maintain a distance of at least 60 cm between the tap head and the socket. The idea is simply to avoid any risk of splashing water on the plug. It is also possible to fit a cap with a hinged flap (closed by default). This same logic applies in similar configurations (kitchen sink, garage sink, etc.).


What are the rules for installing electrical appliances in bathrooms and shower rooms?
What are the rules for installing electrical appliances in bathrooms and shower rooms?
Standard NF C15-100: the different volumes of a bath or shower (containing a bathtub, spa or shower with or without a shower tray or tray) taking into account the fixed walls of the bathtubs and / or showers in the delimitation of the volumes Authorized according to equipment, insulation classes and protection indexes.
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