Waterproof connector box

MOTM

Hi,

I need to connect a new pump to an existing power source lead in a domestic sewage treatment plant. While the connection won't be submersed, it still needs to be fully watertight in case of any overflow/mishap situation (unlikely as that may be) as the connection will be inside the sewage treatment tank. The tank is obviously very humid at all times.

Unfortunately I can't bring the lead from the new pump up to the existing control box as the genius who installed the system first time round appears to have filled the conduit with concrete. The old lead ain't moving.

The connection is a simple live/neutral/earth at both sides.

Any recommendations for a reliable waterproof junction box with good longevity?

Thanks in advance.

Hoagy

A gel filled box like this one is what you need.
Variations of it are widely available in the wholesalers.

2011

I would use one of these

Bruthal

Yea I prefer the hard resin ones myself, but have also used the gel ones, with no problems at all.

Sir Arthur Daley

I would use IP68 mounted socket and IP68 plug, very versilate for future disconnection in repair replacement.

MOTM

Have sourced the resin option nearby so going with that. Will see how it goes after the weekend! Thanks for all the input.

Sir Arthur Daley

Using that joint is so impractical and unnecessary.

Bruthal

It would seem more suitable than a socket in a sewage tank anyway, although maybe the ip68 would do it.

But the resin joint certainly will.

A standard weatherproof box and glands would probably have done here. Gel/resin filled are generally used for being buried, where water is regularly around them.

MOTM

Sir Arthur Daley wrote: »

Using that joint is so impractical and unnecessary.

Bit late now. Purchase made and doing the job tomorrow morning. Pump has a 5-7 yr expected lifespan so no plan to regularly unplug it.

tomdempsey200

something re-useable may have better alright

it will only be a problem if you have to take it out

2011

My concern would be compliance with ATEX requirements.
This may be a potentially explosive atmosphere.

Bruthal

2011 wrote: »

My concern would be compliance with ATEX requirements.
This may be a potentially explosive atmosphere.

There is that alright.

2011

Non-compliance with ATEX directives is a criminal offense.

It would most likely apply in this case: link

It is what caused this incident.

Sir Arthur Daley

Two sewage treatment plant companies I know uses IP68 16amp sockets and plugs in their treatment tanks for the electrical connection.
The tank has the socket screwed on and this is where the incoming cable gets connected, the airater pump comes with a 16 amp socket already on the end of the flex. The socket in question is down low too in the tank.
This is the explanation of my suggestion.

MOTM

2011 wrote: »

My concern would be compliance with ATEX requirements.
This may be a potentially explosive atmosphere.

Are you saying the ip68 may be problematic but resin joint you mentioned earlier is ok (i'm assuming resin joint is ok if made correctly as it is sealed and submersible etc)

2011

MOTM wrote: »

Are you saying the ip68 may be problematic but resin joint you mentioned earlier is ok (i'm assuming resin joint is ok if made correctly as it is sealed and submersible etc)

No, I am saying that I would expect some parts of a sewage treatment plant to have hazardous explosive atmospheres.
If this is the case, which is highly likely then the electrical installation must comply with ETCI National Rules for Electrical Installations in Potentially Explosive Atmospheres, ET105:2011.
This requires special equipment and training. Have a read here.
There should be Hazardous Area Classification drawings for an installation such as this (this is a regulatory requirement).
From these drawings it will be possible to determine if which parts of the installation are in "safe areas". If in the OP's case all of the circuit and equipment that is being dealt with are in a safe are then your solution is perfectly acceptable and compliant.
If not there is a more onerous certification process, more specialised equipment required and the work can only be carried out by suitably qualified personnel. The ETCI have run some training courses recently.
The equipment used is generally very expensive and come with special certification. There is a lot to it and the work can be very specialised.

If there is anything you need to know about it feel free to ask, but most of this work only applies to those of us that work in oil/gas and pharmaceutical projects.

MOTM

on hindsight I've an option to take the connection outside the sewage tank. I think I'll be taking it.

2011

MOTM wrote: »

on hindsight I've an option to take the connection outside the sewage tank. I think I'll be taking it.

Good idea, but this may not solve all of the problems associated with this.
Although this may solve the issue of joining the cable design of the entire circuit should be looked at.
By working on this part of the circuit you take "ownership" of the rest of it.
My starting point would be to look at the Hazardous Area Classification drawings for an installation and unless all of the equipment that you are working on is in a safe area I would walk away if I were you.

Hazardous areas are those defined in the wiring rules as areas of potential explosion risk due to the presence of flammable gas or vapour. In this case I would think that the primary concern would be from methane. The intention is to come up with a sensible design to minimise the likelihood of explosions. This requires a certain level of training and experience.