by ericmark »
Wed Aug 12, 2015 8:00 am
"Can I" is rather a complex question as we have no idea as to the skills of the "I" being referred to or if a scheme member or not or even where they live which would all change the answer.
So I will forget any Part P rules as these vary and just talk about basic electrics.
The fuse in the plug limits the current draw so using multi items is restricted only by the ability to safely retain the cable in the items being used and to be able to distribute the power to multi items.
You can get plugs with up to 4 cable retainers but in the main they have only one so in the main one cable only into a plug. You can get junction boxes with no cable restraint where cleats should be used outside the box to hold cables and you can also get boxes with cable restraints often the maintenance free type have cable restraints built in.
You can use a water tight box with stuffing glands or a box with drain holes or fill the box with either an epoxy resin or a re-enterable compound (Petroleum Jelly for example).
There are many safe ways to do the job which the person responsible for the work can select.
So yes some one with the appropriate skills can do the work you want. But only you know if you have those skills. In the main it's common sense but it is surprising how rare common sense is.
One point I will make. Air expands and contracts so any container full of air will have the air escape when it warms up and when it cools down can suck in water. So either fill with something which is not gas or place where it can't suck in water. Some times it is better to make a hole in the bottom rather than try to seal. When you try and seal it can suck in water from top and blow out air until it fills with water but having even a 1 mm hole in bottom ensures water is expelled again even is a little bit gets in.