# UBL-SR-51

> An address can only have one third line.

Checked against Peppol BIS Billing 3.0 2026.5

Canonical: https://einvoicecheck.eu/rules/ubl-sr-51

## Official rule text

An address can only have one third line.

## Why did my invoice fail UBL-SR-51?

A postal address (BG-5 Seller / BG-8 Buyer, etc.) may include up to three address lines. In UBL the extra lines beyond StreetName and AdditionalStreetName are carried in cac:AddressLine/cbc:Line, and only one such third line (cac:AddressLine) is permitted per address. This caps the structured address at the three lines EN 16931 defines (BT-35/BT-36 and the address line).

## Common causes

- An address contains more than one cac:AddressLine element.
- Multiple free-form address fragments were each mapped to a separate cac:AddressLine.
- Suite/building/department details were split into several AddressLine nodes instead of one.

## How do I fix it?

```
Use at most one AddressLine: <cac:AddressLine><cbc:Line>Building B, 3rd floor</cbc:Line></cac:AddressLine>; put the rest into StreetName / AdditionalStreetName.
```