Dedicated servers are housed in bays. The picture shows D row of bays in room number 1. Each bay houses 42 dedicated servers that are connected to IP network and supplied by internal electric wiring.

Power inputs are on the right of the case and IP network inlets are on the left. The power supply cable is permanently attached in order to avoid accidentally switching it off. The red diode indicates the correct functioning of the server. All 42 servers in one bay need up to 5 kW. In the picture: G bay

The servers are connected on a case of distant reboot named Polgo (previously ouago, apc). Each Polgo manages 24 servers. In every rack, 2 Polgos are set up. Each Polgo is fed by 2 power inputs of 1.25KVA each.

Polgo, conceived and made by OVH, allows to make a hard reboot, which means "off / on" on the power input of a server. Hard reboots are commanded via the manager on the IP network of polgos 24/7. See photo: Polgo nr 250.

Two supply cables of each Polgo pass through the power cabinets. Totally there are 80 miles of cables in the Paris 19 datacenter.

The power cabinets have series of circuit breakers to protect the electric installation from power surges and voltage spikes. Each circuit breaker protects one Polgo inlet.

Power cabinets receive 250kw wattage from our Merlin Gerin power supply. The power supply changes the alternative current (AC) 380V into direct current (DC) and stores the energy in batteries. DC is later used for regenerating the AC of 380V. There is a double insulation between the power input and the power supply. As a result, each power supply is connected to transformer to prevent over voltage.

Power supplies are connected to TGBT (Tableau General Basse Tension- low voltage master distribution panel). We have two TGBTs that work constantly and one spare for an instant automatic substitute in case one of fault. That means if one of TGBT is subject to inspection, in 5 seconds the spare TBGT is tripped. The power supplies provide alternative current for cabinets without any interruption, thanks to energy stored in the batteries. Each TBGT powers 4 supplies.

Every TGBT is supplied by low voltage transformer 1,25 MVA. A transformer changes 20,000V to 380V. Transformers have an oil cooling system. 2 transformers work constantly, the third one is spare.

The 3 transformers are powered by mean voltage station. EDF (Electricite de France) provides 2,2 MVA of electric power for 3 independent inputs. In case of a malfunction of one of them, system switches on the other. In extreme situation, when the second input is faulty, the third one is used. EDF guarantees 100 per cent availability for all 3 inputs. Switching from one input to the other takes 25 seconds.