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We are designing this meter which will monitor house hold consumption. The problem that I am facing right now for days and weeks now, how do I make the meter water proof. I have tried everything but could not find an exact solution.

I tried looked for already made enclosure box that we can use they are a bit expensive as we need bigger enclosure (>240mm) + I dont know who the whole can be air tight when we passing electrical wire through it.

We are also exploring molding option but I dont know what exactly I need. For do I place conducting strips in the mould already which will be my connection point from inside and outside? Or do I drill holes in it and later cover it with some special connectors. Any help is appreciated.

I cam across these types of enclosure (highlighting the joint), should I be using something similar. How do they provide water proofing. What is recommended technique to create water and dust proof isolation for a meter?

Included is my meter design where I need help regarding water proofing.

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  • \$\begingroup\$ You write waterproof, do you mean that the enclosure is going to be submerged, like capable of sitting at the bottom of a swimming pool or do you mean, it will be mounted outdoors and must be able to withstand rain and wind? I think you mean the latter. Beware that making the enclosure airtight might give issues as any moisture trapped inside (condensation!) cannot escape. I strongly suggest that you investigate how similar outdoor units are made and learn from that. You do not want to be making mistakes which are solved in other products already. \$\endgroup\$ – Bimpelrekkie Feb 15 '18 at 10:54
  • \$\begingroup\$ Do you know IP you need? (en.wikipedia.org/wiki/IP_Code) How waterproof does it really have to be? Wouldn't it be wiser to just put the current transformer outside, run the cable thru the wall and have the meter where it' warm and dry? \$\endgroup\$ – Daniel P Feb 15 '18 at 10:56
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Nothing is water proof, not even submarines (sometimes) unless you go for a fully hermetically sealed design and this doesn't sound like an option to me so, you have to design to meet a certain IP rating (where IP stands for "ingress protection"). This is used in the EU but Nema (see below) is used in North America: -

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Then you have to choose appropriate cable glands for incoming cables. They have to have the appropriate ratings too.

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You also have to consider the temperature range that the box may be subject to and analyse how much humidity can be present. Water will get in no matter how hard you try and stop it and humidity/temperature changes are quite challenging. In the end a lot of designs use a drain plug to allow water that has entered by osmosis or capillary action to drain away harmlessly.

If you are in the US this comparison chart may be useful: -

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You probably need an enclosure rated IP65, which is the normal outdoor standard. This is sufficient except where there is persistent driving rain, such as on an exposed hilltop. Cable entry is through waterproof glands, such as the one shown.enter image description here

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You mentioned connectors in your question. If literal connectors, whatever you choose must have the same or higher IP rating and be installed per connector manufacturer's instructions. There are many from which to choose; Turck has a series of connectors that work for my applications.

Whether you use cable glands or connectors, try to locate all entries on the bottom surface of the enclosure to prevent moisture ingress. If they have to be on the side, then a drip loop in the cable will help prevent water from following the cable into the gland/connector. Never place entries on the top surface for wet installations.

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