Panasonic state that a trigger voltage above 24V may damage the camera {this is stated in the manual, Section}. They recommend less than 12V. {To measure the trigger voltage} turn the flash on and measure the voltage between the center pin and the side metal slide {with a multimeter}. Some older flashes have several hundred volts so take care.
{Picture below `Darby Creek'. Taken by Adrian Ashfield with FZ10. If you look in Adrian's galleries using the link above or below, you will find many examples of photographs taken with the FZ10 with a flash and/or low-light conditions.}
Strobe Trigger Voltages -- A list of trigger voltages for dozens of flash units.
Devices are available to reduce the voltages. Steve `ssteppe' (dpreview, Panasonic forum, 12 March) writes...
I purchased the Wein SafeSync for {the purpose of moving an external flash off the hot-shoe} (and also to make sure my Vivitar 283's voltage was reduced to a safe level). You can either attach the external flash to the SafeSync or use the external flash off-camera via the PC connection. I've used it with a PC extension cord to fire a Vivitar 283 in an umbrella (with another Vivitar 283 fired via slave as fill flash).
