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Guide to commercial installations | Part 2 Panelboard: Standards and Regulations
14
Metering
There are many reasons to meter the electrical energy at
distribution boards, typically these may be:
1. To comply with relevant Building Regulations
2. To bill tenants
3. Monitor power use etc.
Building Regulations
Parts L2A and L2B of the Building Regulations cover the
conservation of fuel and power and ensure that building
providers have information to see where energy is being
used. This enables the owner to introduce systems to reduce
this energy use and therefore the building’s carbon
emissions.
While the regulations only affect England and Wales, the
principle is useful for the whole of the UK. They require the
end user to be able to trace at least 90 percent of the annual
energy consumption to end use categories, such as heating,
lighting or power. This is achieved through metering.
The approved document to the Building Regulations
considers that you should install incoming meters for every
building that has a greater floor area than 500m
2
.
It also recommends that any building with a floor area greater
than 1000m
2
has automatic meter reading facilities. You can
provide this by using data loggers that connect to the pulsed
output of various kWh meters in the building; these then
transfer this information over a network. Another alternative is
to use meters with outputs such as MODBUS that provide a
more secure or accurate method of monitoring.
Billing
You can only use approved electricity meters for billing.
This is a requirement of section 7 of the Electricity Act 1989.
Since 2006, the Measuring Instruments Directive (MID)
covers approval for meters to supplies below 100kWh.
Where electricity is to be sub-billed between relevant parties
in commercial and industrial applications, the meters must
meet the requirements of Annex B of MID. For full billing, the
meters must comply with Annex B and Annex F.