Loss or damage by fire to the electrical appliances or installations insured under this Policy arising from or occasioned by overrunning, excessive pressure, short circuiting, arcing, self heating or leakage of electricity, from whatever cause, (Lightning included) is covered subject to the terms and conditions of this Policy, but it is expressly understood that no liability exists under this Policy for loss or damage to any electrical machine, apparatus, fixtures or fitting, or to any portion of electrical installation, unless caused by fire on lightning.
