L2 Building Regulations - the requirement for sub-metering, and the cost-effective use of electricity

Section 3 of the L2 Building Regulations clearly lays out the requirement for sub-metering so that the following areas can be directly measured or reliably estimated:

1. Electricity, natural gas, oil and LPG provide to each separated tenant area that is larger than 500m2.
2. Energy consumed by plant items with input power greater or equal to table 13 of the regulations.
3. Any heating and cooling supplies to separately tenanted spaces (area 3).
4. Any process load that is discounted from the building energy consumption.

Why meter?

The question may be asked - why use energy metering? The answers include the following:

• Metering detects any excessive energy consumption.
• Metering can compare actual and predicted daily usage profiles.
• Metering can explain reasons for over consumption.
• Metering can indicate the monetary cost.

Also….

L2 imposes new requirements for building services. Special demands on the performance of commercial and domestic lighting, space heating and hot water systems.

L2 requires building owners/occupiers account for 90% of each energy source they use.

L2 incoming meters installed in every building greater than 500m2 with sub-metes in each separately tenanted area above this same threshold.

The energy used by plant items above certain power ratings must be individually metered. For example:

• Boilers.
• Chillers.
• Combined Heat and Power plants (CHP).
• Electric humidifiers / Motor Control Centre (MCCs) powering fans and pumps.

With energy price rises already occurring, and likely to continue to rise, energy consumption and management has become a major consideration for business. Therefore measuring how much energy you are using based on the regulations should be a major concern.
Digital energy meters:

Available from ABB is the range of Deltaplus digital energy meters. Deltaplus features include the following:

• CT/VT metering with adjustable transformer rate.
• Tariffs.
• Active or combined.
• 80A direct connected.
• Multifunctional voltages.
• Alternative installation form.
• Automatic installation check.
• Instrumentation (analyser).
• Potential free pulse output.
• IR output.
• Accuracy class 1 or 2.
• Certified to IEC 61036/61268.

Deltaplus applications:

• Blocks of flats.
• Commercial buildings.
• Smaller industries.
• Distribution boards.

Deltaplus technical data:

• Accuracy class: 1 & 2.
• Voltage: 3 x 57-288/100-500V + 3 x 100 - 500V + 1 x 57 - 288V.
• Max current: 6A (VT,CT), 80A.
• Frequency: 50/60Hz.
• Pulse output Max247V AC / DC.
• Max current 100mA.
• Max connection 2.5mm.
• Tariff input: Max276V AC.

Other metering options are available from ABB.