Zoom An unfortunate incident for the BMW Sauber team

BMW Sauber on Thursday insisted there was no danger to either the mechanic or test driver Christian Klien during the electric shock incident at the Jerez test a month ago.

The unnamed mechanic was thrown to the ground briefly hospitalised but not seriously injured, as he tried to wheel Klien's prototype test car, equipped with an early KERS system, at the Spanish circuit.

But while conceding that high voltage was involved, the team's head of powertrain Markus Duesmann denies that the mechanic or Klien were exposed to serious danger.

At the end of a long investigation into the incident, BMW also said Klien was protected by the shock by his racing overalls and gloves.

Markus Duesmann Q&A

What exactly happened in Jerez?
"The mechanic suffered an electric shock after touching the sidepod and steering wheel of the car. There was a high frequency AC voltage between these contact points, the cause of which has been traced back to the KERS control unit and a sporadic capacitive coupling* from the high-voltage network to the 12-volt network. The voltage ran through the wiring of the 12-volt network to the steering wheel and through the carbon chassis back to the control unit."

Was there a serious danger to the mechanic and the driver?
"No, as only a small amount of energy can be transferred through this capacitive coupling effect. However, the energy is sufficient to cause an extremely painful reaction. The driver was insulated against the car by his racing overalls and gloves and therefore not in any danger."

Why did the investigation take so long?
"It was not possible initially to reproduce the capacitive coupling effect in the car, as the problem was caused by a sporadic error in the control unit. Due to the extremely high frequency of the voltage in the steering wheel, the safety mechanisms and data recordings did not pick up on the error. In the absence of data, all the theoretical possibilities had to be systematically investigated and analysed in tests. Furthermore, the capacitive coupling effect only occurs under certain conditions. Without the option of driving the KERS test car used in Jerez again, we had to reconstruct these conditions. We also had to develop a model to be installed between the steering wheel and sidepod which replicated the characteristics of the human body as an electric transfer element."

What measures are now being taken to solve the problem?