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The drivers carry electricity in the dwelling and use constituents with various characteristics. Their choice depends on their location and the power of the devices to power. In all cases, security is in order.

Choosing your ducts and ducts © Hervé Lhuissier

The electric wires must be protected against shocks or accidental contact. They are therefore compulsorily inserted into a sheath. When the installation includes fabric ducts, the latter must first be replaced.

1. A multicolored wiring

Electric conductors

  • The electrical "conductors" consist of a conductive core, usually copper, coated with an insulating PVC tinted sheath, which identifies their function: blue for the neutral, yellow-green for the earth, red and black for the phase.
  • But we also meet other colors (orange, purple, beige, yellow...), especially for circuits back and forth and remote switches. The section of the core of a conductor is a function of the device to be powered: for example 1.5 mm2 for lighting circuits and 2.5 mm2 for plugs or appliances. The soul of a driver can be flexible or rigid: everything depends on the number of strands of copper that compose it. H07 V-K multi-stranded flexible conductors are exclusively for power cords of equipment. Only rigid conductors (in particular H07 V-U or V-R) can supply the circuits of a domestic installation.
  • The "cables" comprise several conductors of identical section, joined together in at least one insulating envelope. In a home installation, the most commonly used ones contain three conductors: one for the phase, one for the neutral, one for the earth.

Minimum section of drivers

The electrical wires must have a minimum section (from 1.5 to 6 mm2) depending on the type of circuit being powered. This section also determines the maximum number of light points or power outlets.

minimal sections of electrical conductors

2. Protective envelopes

Electrical conductor sheath

  • Electrical conductors must never be visible after they have been used: they must be protected by adequate sheaths. Depending on their type, they can remain visible, circulate in the building voids, be embedded in walls, floors and slabs or be buried under the conditions provided by the standard.
  • We distinguish mainly two categories of sheaths: some rigid like the tubes "insulating rigid smooth" (IRL), the other flexible. Often called sheaths, they are the "corrugated ring insulation" (ICA), the "transversely elastic ringed insulation" (ICTA) or "smooth" (ICTL), the "black insulation tubes or ivory branching" (TINB or TIIB) and than the "cable tubes" (TPC).

With the exception of the TPCs, reserved for the strong currents *, each of the other appellations is completed by four digits. The first two symbolize the increasing resistance of the ducts to crushing (1 to 5) and shocks (1 to 5). The last two indicate their installation and use temperatures: minimum (1 to 5) and maximum (1 to 7). The most common conduits are thus type IRL- and ICA-3321, ICTL-3421, ICTA-TINB- and TIIB-3422. Their implementation must respect the prescriptions of NF C 15-100, partly detailed in the "Residential premises" book published by Promotelec.

* 230 V supply circuits

Electrical circuit: ringed hoses

The corrugated sleeves of type ICTA are of different colors (blue, black, white, gray, brown...). These colors have no special meaning with the exception of orange (flame propagator) and green (weak currents). These sleeves exist pre-wired or equipped with a pull-wire.

Electrical circuit: corrugated sheath in prefilated version

Ribbed sheaths have been available for a long time in prefilée version: they save time by avoiding having to introduce the wires... We find especially 3 x 1.5 and 3 x 2.5 mm2 and sometimes 3 x 2.5 + 1 x 1.5 mm2 (supply and control of electric radiators).

3. Calibrate its sheaths

  • The same duct can accommodate several circuits provided that the following requirements are met:

- come from the same branch circuit breaker,
- be individually protected against overcurrent,
- route the same voltage (230 or 12 V...).

  • Whatever the conduits, drivers should not be too cramped. This implies not to use more than a third of the duct section (see table below). At present, this regulatory constraint only concerns drivers to be used in already installed conduits. But we can continue to use it as a reference for any new circuit. Especially when it comes to flexible sleeves that have several elbows and, generally, from a certain length (2 m or more).
  • This relaxation of the regulations is interesting in the context of short straight lengths, for example for a wall crossing. It must be kept in mind, however, that the space available in a duct facilitates the introduction of a new driver.
  • Little trick in the event of intervention on a duct already installed and that the wire-puller blocks: talc or a specific lubricant of the type Yellow 77 constitute good allies.

Conduits: what uses and what size

Depending on their type, the ducts can only be used for certain purposes: embedded in a wall, a slab, etc.

Which electrical conduit for which use

Similarly, their diameter determines the number of drivers they can accept (always keep a little margin in case of elbow).

which electrical duct diameter to choose

Pass electrical conduits in a partition

During a renovation, it is important toorganize the site. The passage of the ducts is carried out parallel to the installation of the dubbing structures, the casings are fixed once the insulation in place.

Electrical circuit: Tracfil wire puller

Pulling several conductors in a sheath involves stripping and twisting them before attaching the end of a wire puller and then coating the whole with adhesive to facilitate sliding.

Electrical circuit: Tracfil wire puller

With this device (Tracfil), it is sufficient to tighten the end of the conductors (stripped) in a warhead tied with the pull-wire.
Save time and ease of installation!

When a sheath has lost its pull-wire, a needle pull-wire advantageously replaces the electric wire that one is accustomed to use to pull the others... The spring located at the front of the wire-puller easily passes the turns (even tight) and the back ring allows to hang the wires securely.

needle puller

4. Installation: recessed or projecting?

  • In habitable volumes, the circuits are primarily recessed in grooves made in the walls or in the thickness of the doubling complexes (see diagram below). A kerf must accommodate only one duct and be deep enough so that the conductor is covered with at least 4 mm of plaster.
  • On the other hand, in basements, attics or outbuildings, ducts are laid projecting. Flame-propagating conduits (ICTA and ICTL orange) can not be embedded in the thickness of an insulator or circulate in structural voids.
  • An implantation rule is however common to both pose modes: the path of the ducts can not be oblique. At least 3 cm must be left between an apparent electrical conduit and a gas, oil or water pipe (20 cm when buried). Subject to being mounted in bricks or breeze blocks, the load-bearing walls allow ducting up to Ø 32 mm.

Waterproof electrical box

In addition to their color, the drywall installation boxes can be identified by their tabs at the top and bottom. Multimaterials also have metal tabs and especially four orifices allowing sealants (plaster, glue...) to flow outward. The airtight boxes have a polymer waterproofing membrane. Depending on the type of box, these covers are larger or smaller to allow the passage of ICTA electrical ducts inside.


Perforated cap for waterproof electrical conduit

Adapted to the diameters of the current ducts (16 to 32 mm), the perforated plugs make it possible to seal their ends, leaving only the conductors passing. This ensures the airtightness of the ducts and ensures the absence of thermal bridges.

Bleeding: strict rules

The position of the recessed sleeves obeys strict rules: for example, it is forbidden to make diagonal cuts.

the rules for digging bloodletting

The nature and the thickness of the partition condition the maximum diameter of the sheath.

depths of grooves for electrical conduits

Recessed Alternatives: Moldings, Chutes and Skirting

Electrical circuit: synthetic profiles

  • Classic ducts have no decorative purpose. Only some IRL are able to get a little forgotten thanks to their white or beige hue. Look for moldings, chutes and baseboards to find more aesthetic products. These synthetic profiles consist of a rear part (bottom) to attach to the wall and a hood that can not be removed without the aid of a tool. Special pedestals for wall outlets as well as various accessories are added: end caps, inside and outside corners, junctions, taps, etc.
  • All must be used to ensure continuity of the degree of protection. TheIP index consists of two independent digits: the first corresponds to resistance to penetration of foreign bodies (0 to 6) and the second to that of moisture (0 to 8). It alone is taken into account in a bathroom: these conduits are accepted only if they have an IP degree at least equivalent to X1 in volume 3 and X4 in volumes 1 and 2.

Electricity distribution

Video Instruction: Electrical Conduit: Types and Uses