Electrical engineering consultancy: Kytom coordinates your installation

The electrical installation of a commercial floor concentrates regulatory and functional constraints that few work packages combine. Three normative frameworks apply simultaneously:

• NF C 15-100 (and amendment A5, applicable since 2015): differential selectivity, cable cross-sections, circuit identification, single-line diagrams.
• Lighting requirements for workplaces (framework applicable since the decree of 5 August 2013): 200 lux in circulation areas, 300 lux in meeting rooms, 500 lux at office workstations.
• Commercial buildings decree (decree no. 2019-771): trajectory of -40% in consumption by 2030.

A modern office workstation requires 6 to 8 16 A sockets per employee, whether for the PC, dual screens, mobile charging, the dock or IP telephony, compared with 3 to 4 fifteen years ago. The densification of connected objects (CO2 sensors, presence detection, access control) significantly increases the number of RJ45 ports required. A large share of projects involves a complete overhaul of distribution boards, either due to undersized subscribed power or non-compliance with NF C 15-100 A5.

When the electrical package accounts for less than 12%: on a recent floor with a main distribution board compliant with NF C 15-100 A5 and sufficient subscribed power, the envelope drops to 8-10% of the works. A dedicated engineering consultancy is then not justified: a sign-off by a Qualifelec-certified electrical contractor is sufficient. Kytom flags this from the week 1 audit to avoid an oversized assignment.

For the CFO and the Asset Manager: the cost of an unframed engineering consultancy

The electrical package reads as OPEX as much as CAPEX. Three items weigh on the operating account and the asset value:

• Commercial buildings regulatory trajectory: a floor off the -40% trajectory in 2030 is exposed to an administrative fine of up to 7,500 EUR per site (art. L174-1 of the Construction Code). Lighting represents 20 to 25% of commercial building consumption. An engineering consultancy that specifies controlled LED and dimming in the technical programme secures the regulatory trajectory and the rental value over 10 years.
• Enedis lead time on power: switching to the yellow tariff requires an 8 to 14 week LV connection lead time beyond 36 kVA. On an 850 m² floor leased at 350 EUR/m²/year, each week of delivery delay represents around 5,700 EUR of rent paid outside of operations. An insufficiently framed preliminary design multiplies modifications in the execution phase, generating amendments that can reach 1.2 to 1.5 times the initial price of the package concerned.

The Asset Manager’s reading is different: a main distribution board compliant with NF C 15-100 A5 and a documented BMS (complete as-built file, open supervision such as BACnet) are valued in due diligence. Contrary to common practice, Kytom recommends pricing the BMS as a separate option from the main contract: this allows the Asset Manager to arbitrate according to the holding period, without renegotiating the electrical contract.

The Kytom method in 5 steps set over 12 weeks

The management of electrical engineering consultancy follows a sequence reproducible across Kytom’s 11 offices, which secures multi-site groups.

1. Audit of the existing setup (5 days): survey of boards, measurement of power demand, Consuel check, lease review.
2. Technical programme: translation of the fit-out project (open space, meeting rooms, phone boxes, kitchenette) into a high-current and low-current specification, with target ratios validated by the CFO or office manager.
3. Consultation and plans: the engineering consultancy produces single-line diagrams, DIALux calculations (500 lux maintained at 80% of workstations), category 6A VDI schematics. Kytom challenges each assumption over 2 technical meetings.
4. Contractor management: validation of technical data sheets (LED luminaires >100 lm/W, 5-year warranty), monitoring of Consuel tests, clearing of reservations.
5. Acceptance and as-built file: delivery of the complete file within less than 15 days after handover.

MEP coordination under the raised floor is a critical point: a raised floor of 100 to 300 mm in height accommodates four parallel conduits (air, high-current electrical, VDI, condensate) that impose strict sequencing between work packages.

Measured benefits on budget, energy and schedule

Kytom’s coordination produces three concrete effects on commercial projects.

From an economic standpoint, the upstream arbitration of technical choices (luminaires, cable trays, BMS controlling lighting and HVAC) reduces the electrical package budget by 8 to 12% compared with a direct consultation.

From an energy standpoint, the switch to controlled LED with presence detection and daylight dimming generates substantial savings. According to the CSTB (RT 2000), for 2500 annual hours of use of premises with access to natural light, full-power electrical lighting is only necessary 150 h/year, or 6% of the time (AFE). This trajectory contributes directly to the Éco Énergie Tertiaire scheme, which requires a reduction in final energy consumption of at least 50% by 2040 compared with 2010.

From a scheduling standpoint, upstream engineering framing strongly reduces the volume of modifications during the construction phase. The compliance of contractor partners secures acceptance without reservation, with a Consuel certificate issued for any new or significantly modified installation.

When a BMS is not justified: on a floor of less than 400 m² with fixed hours and a small team, the return on investment of a BMS controlling lighting and HVAC generally proves too long to be justified. Presence detection per luminaire and a programmable thermostat are sufficient. Kytom recommends this explicitly in the technical programme to avoid over-specification.

Three points of vigilance: Enedis, landlord, co-activity

Three limits must be anticipated from week 1, otherwise delivery may be pushed back by 4 to 8 weeks.

• Enedis subscribed power: in an older commercial building, increasing power (switching to the yellow tariff) imposes a lead time of 8 to 14 weeks (Enedis schedule Conditions de raccordement BT >36 kVA 2023). Kytom files the request in week 2 of the schedule, even before the contractor consultation.
• Landlord agreement on the main distribution board: any overhaul of a main board by the tenant requires written agreement from the landlord (standard clause of the 3-6-9 commercial lease). The review period varies from 3 to 6 weeks depending on the institutional property concerned.
• Co-activity with adjacent packages: the pulling of high-current and VDI cables must precede the installation of the suspended ceiling and follow