electricalforum.nz

While I always avoid joints in TPS cable runs, I have a situation where extending an existing cable with a joint is unavoidable without major building disruption. My concern is this connection will be sealed in the ceiling space and will be unaccessible in the future. It's a low current 1mm2 lighting circuit.

Studying 3.7.3 allows this practice, with additional requirements from 3.7.2. However ESR20 (2i) lists the maintenance access requirement.

Screw connectors in a junction box would in my opinion have a "maintenance" aspect. If using inline crimp connectors with heat shrink, which product range does everyone trust?

For stranded cables, crimp joins are perfectly acceptable under those clauses.
Ordinary sleeving provides conductor insulation; and and heavy-duty shrink sleeving provides an adequate re-instatement of sheath.
However most 1 mm2 TPS in NZ is single-stranded, and that doesn't take crimp joints well.
In fact I am not aware of any crimp terminals designed for use with this type of cable.

Agree there is a risk of loosening over time with any screw-type terminal; and therefore an ongoing access requirement.
These days there are other terminal types, eg spring terminals, that would avoid this problem.
Eg Wago 222-413
Or revert to old-fashioned ways, with twist-&-solder.