Annex 1

Annex 1 is the primary source of CDCM (Common Distribution Charging Methodology) tariff data within each DNO's annual charging statement. It contains the 32 standardised tariff categories used across all 14 GB DNOs since April 2022.

What Annex 1 contains: For each of the 32 CDCM tariff categories, Annex 1 publishes 7 charge components:

• Red Rate (p/kWh) - Peak period unit charge
• Amber Rate (p/kWh) - Shoulder period unit charge
• Green Rate (p/kWh) - Off-peak unit charge
• Fixed Charge (p/MPAN/day) - Daily standing charge
• Capacity Charge (p/kVA/day) - Based on agreed capacity
• Exceeded Capacity (p/kVA/day) - Penalty for exceeding agreed capacity
• Reactive Power (p/kVArh) - Charge for poor power factor

Annex 1 vs Annex 3:

• Annex 1 contains active/open tariffs that can be assigned to new connections
• Annex 3 contains preserved/legacy tariffs for closed LLFC codes

Publication cycle: Annex 1 tariffs are updated annually, typically effective from 1 April of each charging year. DNOs publish draft rates in autumn for consultation before finalising.

Why Annex 1 matters: This is the authoritative source for validating DUoS charges on business electricity bills. If your bill shows different rates than those published in your DNO's Annex 1 for your tariff category, that's a billing error.