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Unfortunately, in reality, it's almost always possible for an end user to demand more than their supply is capable of handling, which is why OCPDs are installed. Take a look around your home and ask yourself what would happen if I plugged a 3kW kettle into every socket in my kitchen.

The OCPDs in the board are there to protect the installation wiring and little else and the suppliers OCPD is there to ensure the install as a whole doesn't exceed it's capabilities.

But it's still not clear what's tripping, and when the tripping started. You're just basically pointing the finger at the spark who you've been told designed and installed this 4 years ago, so I'll say this... if these tripping problems were not present when the installation was signed off 4 years ago (if they were, they should have been reported to the original contractor), and only started in say the last 18 months or so I'd suggest the client has changed something and introduced equipment that pushes the demand beyond the capabilities of the installation (as designed 4 years ago based on the information available to the spark at the time).

I actively try and encourage my clients to include some additional capacity 'for the future' but there comes a point where it's not practicable or financially viable. If it was a new business, they possibly had budget constraints so the spark may have been financially impeded. There's so many factors that could have played a part in his decision making process and you can pretty much guarantee you won't get the negative points from the client since they obviously want you on their side.
 
Unless I have missed it SC there is no mention of tripping circuits so I am still confused what he has been asked to advise on.
 
Sorry don't get that.

The calculations based on projected demand vs the limitations actually implemented by the solution which appear to fall short of what is required in this case. Somebody used the term "likely" earlier on. That's a term used when referring to chance and probability. I don't believe anything should be left to chance where safety is concerned. Demand is easily definable and providing a delivery mechanism that meets the demand is also straight forward. There's no reason why chance should play a part. The numbers in this case don't line up. Too much left to chance. Alarmingly so.
 
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Unfortunately, in reality, it's almost always possible for an end user to demand more than their supply is capable of handling, which is why OCPDs are installed. Take a look around your home and ask yourself what would happen if I plugged a 3kW kettle into every socket in my kitchen.

The OCPDs in the board are there to protect the installation wiring and little else and the suppliers OCPD is there to ensure the install as a whole doesn't exceed it's capabilities.

But it's still not clear what's tripping, and when the tripping started. You're just basically pointing the finger at the spark who you've been told designed and installed this 4 years ago, so I'll say this... if these tripping problems were not present when the installation was signed off 4 years ago (if they were, they should have been reported to the original contractor), and only started in say the last 18 months or so I'd suggest the client has changed something and introduced equipment that pushes the demand beyond the capabilities of the installation (as designed 4 years ago based on the information available to the spark at the time).

I actively try and encourage my clients to include some additional capacity 'for the future' but there comes a point where it's not practicable or financially viable. If it was a new business, they possibly had budget constraints so the spark may have been financially impeded. There's so many factors that could have played a part in his decision making process and you can pretty much guarantee you won't get the negative points from the client since they obviously want you on their side.

Maybe I'm splitting hairs here but it IS possible to demand the resources. But what you are sdaying it's not possible to deliver it because the OCPDs will prevent it from being delivered. Yes. I know. But its better, in my opinion, if you can design the layout so that the demand doesn't outreach the supply. That's also possible.
 
The calculations based on projected demand vs the limitations actually implemented by the solution which appear to fall short of what is required in this case. Somebody used the term "likely" earlier on. That's a term used when referring to chance and probability. I don't believe anything should be left to chance where safety is concerned. Demand is easily definable and providing a delivery mechanism that meets the demand is also straight forward. There's no reason why chance should play a part. The numbers in this case don't line up. Too much left to chance. Alarmingly so.
There you go then the system was badly designed for its intended purpose. State your findings in a Report and job done.
 
Ok. Thanks to everyone for their input. I have what I wanted from this post. That's great. I appreciate it. Just to be clear. When I posted this it was because I was looking for opinion more so than advice. I know that there is something not right about this setup. I knew it when I started listing the devices and looking at the layout. I am alarmed by what the numbers revealed. But I am very particular when it comes to theory and best practice. I appreciate that not everyone is as pernickety as I am and what I wanted to do was get a feel of how others would approach this situation. What I have found is that there seems to be a mixture of feedback. Some find these numbers as concerning as I do, others seem to be happy to leave it to chance and other still don't actually see a problem. I will take the data logging suggestion forward. That seems like a good idea and straight forward enough. But there will be changes recommened to the supply layout in the interest of safety. That is for sure. I think it would be remiss of me not to do so. Thanks again.
 
I'd say if the numbers that alarm you are based on your earlier allowance of 13A per 13A outlet, then that assertion is the problem with the numbers.
 
I'm guessing I fit into the leave it to chance or the don't see a problem category and if that's your opinion, you've failed to understand my line of questioning.

You still haven't answer what I consider to be fundamental questions... when did this tripping issue start? and what is actually tripping and when?

You've not provided a complete breakdown (per item) of equipment and you personally have no way of knowing whether it is the same list that was supplied to the original spark. A complete breakdown would allow a proper assessment of diversity (which in case you're not aware Ray is the method by which we regularly undersize supplies).

Why I'm challenging this is because as per bloody usual, there's a significant amount of 'must be the sparks fault', 'poor design' without actually knowing the full story. Melted plugs and sockets does not necessarily equal poor design... poor quality accessories, poor terminations maybe but it definitely doesn't automatically mean poor design.
 
And another side step of my question.

If you go in all guns blazing making statements the installation is not up to scratch it could have serious ramifications for someone's business. Do I think there are some not so good decisions based on what you've said... yes. Do I think there could be mitigating circumstances... maybe. New install for a new business, possibly budgetary constraints and he did the best he could? Who knows. Certainly none of us do.

If this tripping is a recent turn of events, you should perhaps proceed on the basis that things have changed, probably around the time the tripping started.

Could be the installation was perfectly good for what was there 4 years ago, but isn't up to the demands of the business now.
 
And another side step of my question.

If you go in all guns blazing making statements the installation is not up to scratch it could have serious ramifications for someone's business. Do I think there are some not so good decisions based on what you've said... yes. Do I think there could be mitigating circumstances... maybe. New install for a new business, possibly budgetary constraints and he did the best he could? Who knows. Certainly none of us do.

If this tripping is a recent turn of events, you should perhaps proceed on the basis that things have changed, probably around the time the tripping started.

Could be the installation was perfectly good for what was there 4 years ago, but isn't up to the demands of the business now.

As I said ealier this posting was not smuch a plea for advise or diagnosis. It was a straw poll on my interpretation of the findings. It appears opinions vary which is fine. Thanks for your input.
 
I am in agreement with Sparkychicks reply(s)
we have both asked regarding the equipment that is being used.
I think we are all in agreement that a load logger would be a great
source of providing load information.
You keep on saying "numbers" what numbers?
There should be an O&M manual with "as fitted" drawings this may show what was designed for then and could show what load has been added.
The burnt out plug and sockets would probably down to poor contact did the equipment come with a moulded plug or has this been added to something that was designed to be hard wired on a dedicated circuit.
What effect is this load having on the 3 phase supply and is it maybe overloading one of the phases on the D.B?
 
As I said ealier this posting was not smuch a plea for advise or diagnosis. It was a straw poll on my interpretation of the findings. It appears opinions vary which is fine. Thanks for your input.

Blown away by this post.

Sound out of your depth mate tbh.

Confirm if Iz>In for that 63A sub then forget about it for now.

You've got 13A sockets melted and your worrying about the OCPD upstream of the one protecting the circuit in question.

Also, diversity......wtf......you've got the actual install in front of you. You need to get a clamp meter out.

Probably nothing more than 3kW appliances plugged into sockets running for long durations.
 
As others have now said, you don't seem to have any awareness of diversity and how it is applied. Taking your example of plugging a 3kw kettle into each outlet, you wouldnt be able to turn them all on at once, empty them and refill them all at once, and turn them back on again. So even if you were making 500 hot drinks, its likely only 3 or 4 would be on at once, as the others would be being used/refilled. This principal is applied to most electrical loads in some way, especially heating loads controlled by a thermostat, which can be cycled.

It does sound like more capacity is now needed in your installation, but until you find the actual numbers for what is being used, and how and when, you wont know this for certain.

As for the safety aspect, running an installation constamtly at 100-120 percent of its capacity will significantlt shorten its life, and if this is the case it needs to be upgraded. But as mentioned, providing the OPCDs are correctly sized for the cable they will operate before the cables overheat.

And to give you an idea of how diversity is applied, i believe the national grid used to allow for 1kw per house (it may be slightly higher than this now but i dont think by much)
 

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