Waterproof Electrical Cable Wire Connector - Outdoor Cable Connector, Outdoor Electrical Junction Box, IP68 Junction Box Cable Connector Sleeve Coupler For 2 Or 3-Pin Cables, -40°C +95°C

There are special connectors for outdoor equipment, you can even buy a type that becomes a plug so you can have a short lead on the tool and then a longer lead you can then plug into the tool. https://www.screwfix.com/p/masterplug-nc102o-10a-2-pin-connector-orange/46232 or https://www.amazon.co.uk/Mwqpgyh-Waterproof-Electrical-Cable-Connector/dp/B0D7BBZPGK?source=ps-sl-shoppingads-lpcontext If you use the screwfix type, make sure the pin side of it is on the tool, if you have it on the lead side the pins will be live when plugged in. You can also get a RCD type of the Amazon one from Screwfix.