We’ve been asked how it is possible to lock a manhole cover to a drain system or subway. There are some specialist locking manhole covers but they require some significant changes to the rim of the cover and the cover itself which can be shockingly expensive.
The low cost or DIY way to achieve this is to use steel loops fixed into the concrete surrounding the manhole or sections of flat bar bent at right angles and with holes drilled in. Either way another piece of flat bar or solid round bar can be use to secure the manhole. If a round bar is used then you need to drill a hole in one end about 1mm larger than the padlock shackle. There photos help illustrate what I’m trying to explain:
Using flat bar
Fixed at one end
Using tube bar with a padlock on the end.
