Installing Recessed Consumer Unit - De rating MCBs & RCBOs FACTS
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- Опубликовано: 15 окт 2024
- Major flood damage resulted in loads of remedial works on this one. Including changing the consumer unit to a CPfusebox recessed board.
This included using contactum blanks as someone forgot to order CPfuse box ones aka me!
This was installed on a block wall studded out on a steel framed wall. Tails sealed into the cavity behind the Consumer Unit and through the plasterboard at the top of the false wall. No fire seal in the consumer unit! What do you have to say about that one lol.
Mattie swapped out the heating wiring centre and we restored peace to a troubled install!
Here is the wiring matters link I mentioned in the video electrical.the...
#electrician #consumerunit #sparky
Really enjoying the content on the channel mark and love the balance between educating and vlog
Very kind mate. Thank you!
Good shout, excellent IET article, well defiantly have to stop to think about that one more often, so moving forward knowing that the we are generally getting more warm weather and we want to keep the heat in everywhere and rise in materials costs etc, prices will have rise even more to potentially accommodate the need for bigger or vented boards or bigger cabling or both, it just gets better😕
Yes for me its more warm plant rooms in terms of heat and we consume more energy inside enclosures. The biggest issue in this application is using them in colder unheated areas. That moves more towards the line of safety rather than premature tripping. Places in domestic such as sheds and garages. Either needs to be designed in or consider mccbs.
Interesting video and comments. With some sparkies now favouring to install radial circuits on smaller rated MCBs instead of ring mains on traditional 32A MCBs, there is more chance of the former circuits operating more towards their MCB rating. Like you said, it doesn't help that instructions from manufacturers differ sometimes.
Yeah, the issue would be if it's consistently loaded. Unlikely on well designed socket circuits.
It's worth mentioning that its the percentage of max load that's important for protective devices. A 6A RCBO with a 6A load will dissipate almost as much heat as a 32A RCBO with a 32A load. Luckily in domestic most lighting circuits have small loads.
Like Mark says the only big devices likely to get hot in a domestic sittuation are those protecting EV charge points, heat pumps/electric heating, immersion heaters and kitchens to some extent.
Try to give these some extra space and use next size up for breakers, for example 40A on a 32A EC charge point.
Yep any circuit were the load is anticipated to be towards the OCPD max rating for beyond 1 hour will most likely require this. Good design removes this scenario from any probability in most cases. But the ones to watch are as discussed. EV, Hot Tub, PV, Heat Pumps, Immersion elements. Its not a common problem tbh but one to keep a mindful eye on.
Great one again Mark, I am glad you have done one with recess Fusebox as I like the Hager one as you can install it in a plasterboard wall. Not sure if you can do it with the Fusebox. Regarding the derating of MCB/RCBO, I take it is more to do with the magnetic element?
Thermal and magnetic mate
Agreed with what you say, How often does a circuit pull full design load? rarely, all at the same time very rarely!
For sure.
Why can’t I find any wrong with you that I can have moan about ,I’ve tried and I can’t find anything , you’re just to good at what you do 👍👍😂
Be interesting to see how large current draw will affect afdd as they have small CPUs in them.
Yes that is a whole new element to consider for sure!
Lovely job done there mate, I like the reseat fuse box CU 👍
We’re did you get the glow in dark screwdrivers ? I like them be great when I am in a dark place like the loft . Or under the stairs.
Fantastic video guy’s as always mark 👍👍👍👍❤️
Those are made by CK mate. Goole CK glow in the dark screw drivers. I got them in the local wholesalers ages ago
@@electrician247 found them on Amazon for £40+£7.99 p&p ? No thank you 😂
Hi is that fuse box just a normal one and that frame seperate. How dose it screw In did you have to build a frame for it
Yes mate. It's the normal CU. With CP fusebox you buy the frame and it site on the normal CU. Just be careful to get the right size. Frame has 4 fixings in the side which can be secured to a frame and also clamps between the front cover and rear housing.
Nice simple solution tbh.
@@electrician247 okay mate if you install another one you should record it. Looks a nice neat finish in the end. I do like fuse box equipment seems decent quality for the price
So with derating, the old method of having the biggest breakers next to the isolator (based on a rather dodgy premise of the bus bar dropping voltage/heating) is hopefully no longer valid. Now better to "stripe" the actual usage of the breakers to avoid grouping heaters, and consider having the highest constant consumer in the last busbar position.
Yes in essence that is a sensible approach. But remember it is only an issue of you size your breakers close to the running current in the circuit and for a prolonged period. I would have no issue with socket finals and cookers for example living in harmony side by side as they have done for decades. The issue sits around heating, ev, hot tub ccts etc. Again generally we are specifying ocpd way beyond the running currents in most cases. But arranging circuits with this in mind is a good shout.
Nothing wrong with spacing things as such aside from the cost/space burden the client picks up.
Hi Mark.
When a friend did an 18th edition course with sparky ninja. He said that Fusebox rcbo’s at that time could lose up to 50% of their value at higher running temps
I never did that spacing rubbish but what I do, is to space them high and low. So ring then lighting, then cooker, then boiler (6A) etc, etc.
De rating is a factor if you run the devices close to their limits and for prolonged periods. In most designs it is not really a factor at a domestic level. We are designing well under the OCPD values. As mentioned in the video its only really heating and vehicle charging were it might raise its head. A few poorly worked out examples are in place on RUclips which resulted in the trend at the time of spacing all ocpd. Which drives up cost as clients end up buying bigger consumer units. These kind of things are basic sparky skills and unfortunately when some want to create headlines and draw attention towards courses that goes out the window. Is what it is. Your suggestion makes sense but remember the issue is with running currents close to the value of the OCPD. So even what might be considered low power such as 6A lighting could be an issue if you run close to the 6A consistently. More of an issue in cold space imo.
@@electrician247 great points made there 👍 like you say it’s down to loading. I mainly do it so you don’t end up with a hob, a double oven supply and a heavily used ring together. I’ve seen old boards where you can see the tarnished busbar and discoloured devices. More of habit now I think.
Keep up the good work.
@@yrification yeah like I said in the video. Makes sense when you think about it. You are dead right the old school mindset was always biggest to smallest. Don't it for decades myself tbh 🤣🤣🤣
This industry is full of Chinese whispers, and RUclips highlights them. And where a fuse board is concerned they seem to get worse. There's nothing ever been in the regs to my knowledge about leaving gaps next to breakers or the arrangement, we have always been taught to go from highest to lowest.
I have started leaving gaps, but that's only for future additions, so anyone adding a circuit can do so without having to re-configure the board.
👍