Sink waste Thread Size

13 Feb 2016
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United Kingdom
I'm installing a new sink in our kitchen, and am at the stage of installing the waste pipe work.

The threads that connect the pipework to the sink waste, are they all the same size?

I ask as p traps come in 32-38-40mm sizes. I am assuming this is just the connecting pipe OD size and doesn't relate to the thread size of the trap?

Also, I've got 43mm OD pipe going outside, can I use a universal 40mm trap to connect to this?

Best Wishes

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Standard thread. for a kitchen sink you need a 1½" / 40mm trap. Waste pipe could be either solvent weld or push fit - a 40mm compression fitting will fit both.

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