Penalty in case of default of payment of charges

(1) If a person liable for payment of any charges does not, within thirty days of the service of the notice of demand on him under section 55, pay the sum due, he shal deemed to be in default. (2) A person in default shall in addition to the charges due, including interest and demand fee, be liable to pay such penalty as may be determined by the Board, extending to such sum not exceeding 20% of the amount of the charge and the same penalty shall be recoverable along with other arrears.