Connect Garden Hose Thread (GHT / NH) to 1/2" BSP parallel (G1/2 / BSPP)
How to join 3/4"-11.5NH and G1/2, and what stops it leaking.
Not a direct fit. Joining Garden Hose Thread (GHT / NH) to 1/2" BSP parallel (G1/2 / BSPP) needs a GHT female to 1/2 BSP male adapter.
The adapter to buy
A GHT garden hose reaching a 1/2 inch BSP indoor tap needs a GHT-to-G1/2 adapter. The BSP end seals on a washer at the face; the hose end seals on its own coupling washer. Confirm the tap is G1/2 and not G3/4 before buying.
Do not stack a GHT-to-BSP adapter on top of a G1/2-to-G3/4 step and hope. Two dry metal steps weep. Buy the single GHT-to-G1/2 part with a captive washer.
Related connections
Sources: ASME B1.20.7 (garden hose / GHT / NH threads) · NPSH / NH / NHR hose coupling thread table, Fittings.space · ISO 228-1 (G / BSPP parallel pipe threads) · BSP thread dimensions chart (ISO 228 / ISO 7), AmesWeb