MHHS

Industry Update

What This Means for You

As part of the Market-wide Half Hourly Settlement (MHHS) programme, there are industry-wide changes to how electricity meters are recorded. The most visible change is the replacement of the 3-digit MTC (Meter Timeswitch Code) with a 4-digit SSC (Standard Settlement Configuration).

We’ve been preparing for this milestone and want to reassure you that our software is up to date. Here’s what you need to know:

Software Changes Already in Place

We’ve made several updates behind the scenes so you can continue working without disruption:

• Flexible MTC/SSC field – the "MTC" field can now accept either 3 or 4 characters, meaning you can store either the MTC values or the new SSC codes.
• Migration tracking – each electricity meter screen now includes a "MHHS – Migration Complete?" checkbox, letting you record whether a meter has been migrated into the new settlement arrangements.
• Top Line Support – when you add a new meter via our Meter Lookup tool, the SSC will be pulled through automatically. You can also manually update top lines or use our Meters Update import for bulk changes.

What This Means for You

• The SSC update is the most significant change to date, but it does not require large-scale software updates. You can continue to use the system as normal.
• Supplier communications may vary, but we’re monitoring these closely and updating our software wherever needed. For any specific queries about MHHS, we recommend speaking directly with your supplier/s.

Want More Detail?

We've pulled together some FAQs on how our software supports MHHS, covering:

• How top lines are managed
• Matrix pricing and when it’s affected
• What “DUoS Tariff ID” means
• What happens when moving from NHH to HH under MHHS