Hybrid vehicles use high voltage batteries and electric motors to achieve their fuel economy gains. The battery
packs quite a wallop, 144 volts on a Honda Insight or Civic, 201 volts on a second-generation Toyota Prius. This is more than enough juice to toast anyone who accidentally comes into contact with the high voltage battery, wiring or powertrain components
HYBRID ELECTROCUTION HAZARD?
So how does a modern day hybrid vehicle compare to an electric chair? The hybrid comes
in a close second. In days gone by when criminals were executed by electrocution in an
electric chair, a initial jolt of 2000 to 2450 volts was applied to lower the resistance of the
skin. This was followed by a sustained 8 amp current of 400 to 480 volts for 20 to 30
seconds to finish "cooking" the victim. It was an effective means of ending a person's life.
Except for the initial high voltage jolt, a hybrid electric system has the same lethal potential.
The high voltage components in most hybrids are color-coded ORANGE, and on the Toyota hybrids the battery
pack relays automatically open and disconnect the battery if a collision is severe enough to deploy the airbags.
But that's no protection for technicians who may have to service these vehicles.
The recommended protection is to wear Class 0 rated insulated gloves, which are rated to 1000 volts AC, and
must not have any tears, pinholes or cuts. You should test the integrity of the gloves by rolling them up toward the fingers to see if they hold air. If they do not, throw the gloves away and buy new gloves. You should also use insulated tools when working on high voltage hybrid components.
Also, you must make sure the vehicle is OFF before you begin any electrical or mechanical repairs on any hybrid powertrain components.
Actually, hybrid vehicles are not as dangerous to work on as they might seem at first. If the key is off and the key is out of the vehicle, the hybrid system is powered down. The battery can't shock you unless you go poking
around the high voltage battery connections with bare hands or uninsulated tools. Even so, always treat the high voltage hybrid battery and electrical components with caution.
Always disconnect the high voltage hybrid battery BEFORE doing any major repair work or electrical
work. See the instructions in the vehicle owner's manual or manufacturer service literature for details. Most
manufacturers also recommend waiting 5 to 15 minutes before working on the vehicle after the battery has been isolated or disconnected. This gives the high voltage capacitors time to discharge so there is no residual voltage to pose a shock hazard.