Replace circuit breaker with WIFI smart metering circuit breaker

[Tony59]

I want to monitor how much energy our electric shower is using. The shower is currently on a Hager MTN132 B32 MCB.
I assume that this Hager MTN132 B32 MCB goes on to a busbar and has a single live wire connection at the top.

On Amazon and eBay, I have seen MCB's that have WIFI functionality which include metering and other programmable functions (see photo).
However these MCB's seem to have 2 (N&L) connections both at the top and bottom, like a double pole switch. So I wonder if they can be used to replace my Hager MTN132 B32.

Does anyone know if I can just swap these MCB's?
Can I just connect the live wire into the 'L' terminal at the top. Then connect the 'L' terminal at the bottom into the busbar?
Can I leave the 'N' terminals empty? Or does the new MCB need to be attached to the DIN rail without any busbar and have the shower circuit wired through both N & L terminals, like a double pole switch?

Thank you in advance.

 

[ebee]

As it stands you would struggle to connect it in most consumer units.
However there are some Irish consumer units (GARO) that have a double buss bars for MCBs/RCBOs so it might fit those.
The easy answer though would be to mount this unit in its own enclosure and feed this from you existing consumer unit (Where the outgoing shower circuit is now connected) then on the output side of this WiFi unit connect to the shower cable.
In other words the circuit would run, like now, from your existing MCB then to this new unit and hence give you monitoring etc.

Actually, if you have a spare way in your consumer unit and it`s at the end of your existing buss bar then you could cut off the end of the buss bar and fit that WiFi thinghy there, no need for the separate eclosure proving that the new unit fits ok in your consumer unit

 

[Harry Bloomfield]

What about the need for it to be protected by an RCD?

 

[ebee]

Well if it is already protected by an RCD then it still will be if it is done as I explained.
I know I`ve said before, I am a Front-Ender - years gone by RCDs came into vogue, there were DP size like a consumer unit isolator and they were used as A) stand alone in a box after the Fuse or Breaker to cover one circuit or B) used as the Main Isolator in the Consumer unit . Thru various stages the designs progressed into what we have today but many of us started out with rewireable fuses and no RCD unless you were using a TT system and the it was an Earth Leakage Circuit Breaker either Voltage or Current operated.

We did not see many piles of dead bodies in the streets back then in the Pre-RCD days.

I will not mention many cases of copper wire or six inch nails replacing the DNO cut-out. Shhhh !!!

 

[EFLImpudence]

We did not see many piles of dead bodies in the streets back then in the Pre-RCD days.

As has mentioned here before - a huge expense for a benefit that could only be negligible

 

[mattylad]

You would be better off with another energy monitor type.

These wifi breakers are all Chinese made struff thats only popular because they have the wifi gimmick.

A Hagar MCB is a a far better protection device, it's known and trusted more. (AIUI).

 

[ericmark]

To use any device in a consumer unit, it must be sanctioned by the consumer unit manufacturer, to retain its type testing.

So you will need to fit a tongou consumer unit, which needs notifying to LABC so will not be cheap.

 

[JohnW2]

Well if it is already protected by an RCD then it still will be if it is done as I explained.

Quite so. ... and if it wasn't already protected by an RCD, then it still wouldn't be

I know I`ve said before, I am a Front-Ender - years gone by RCDs came into vogue, there were DP size like a consumer unit isolator and they were used as A) stand alone in a box after the Fuse or Breaker to cover one circuit or B) used as the Main Isolator in the Consumer unit . Thru various stages the designs progressed into what we have today but many of us started out with rewireable fuses and no RCD unless you were using a TT system and the it was an Earth Leakage Circuit Breaker either Voltage or Current operated.

You and me too.

We did not see many piles of dead bodies in the streets back then in the Pre-RCD days.

Very true. As I frequently say, if the amount that has been spent on RCDs (presumably well over $1bn in UK) had been directed elsewhere (e.g. to issues related to road safety), then I feel sure far more lives would have been saved.

It really has never been rocket science - although perhaps surprising, the number of UK domestic deaths due to electrocution which might have been avoided by RCD protection has always been so low that there has never been scope for any 'measure' (like the installation of countless millions of RCDs) to save many lives.

Kind Regards, John

 

[ebee]

I must admit, I do feel happier with rather than without an RCD though and the cost of them is not that great, just like I feel happier with MCBs rather than a rewireable fusewire. SPD Ok not a bad idea, AFDD well I have yet to be be convinced. PS, my RCD is AC. However, for customers I usually talk em round to a plain switch & RCBOs, it`s what I would have meeself if I changed my consumer unit and whilst doing it I would put an SPD in. In practice a front RCD has not been a problem for all these years, however I do realise that yes there is a potential for it to be so in comparison.
Myself I would not choose to put one of those WiFi monitors in but if the OP wants one then fair enough he has a choice. By the way I have asked the manufacturer for the accuracy, hopefully I will get an email reply. I think at my age I don`t need to monitor how much power I`m using as a domestic user because I`m one of the "save a shilling" mentality anyway, a smart meter would not benefit me either. But some folk might benefit.

 

[JohnW2]

I must admit, I do feel happier with rather than without an RCD though ...

I suppose that, in some senses, so do I - but I wouldn't regard it as particularly rational, since I feel sure that I actually face (and 'accept', without any real concerns) far greater potential risks as part of everyday life than I would by not having RCD protection in my electrical installation.

..... just like I feel happier with MCBs rather than a rewireable fusewire.

In my case, I would say that my preference for MCBs is really only a matter of 'convenience', not 'safety' considerations.

SPD Ok not a bad idea,

SPDs really have very little to do with safety (of human beings, or even animals), the alleged value being in relation to the protection of equipment from damage - and since, in many decades, I have seen so few cases of unexpected/unexplained 'equipment damage' (which may possible have been caused by supply spikes/surges) that I'm not sure that I will ever be convinced that they are worthwhile (in domestic installations)

AFDD well I have yet to be be convinced. PS,

Same here, and from what I know so far, I am not at all sure that I will ever be convinced, at least in relation to domestic installations.

my RCD is AC. However, for customers I usually talk em round to a plain switch & RCBOs, it`s what I would have meeself if I changed my consumer unit...

I have about a dozen RCDs. All are Type AC and I lose no sleep over that. However, not the least because of the regs, I would certainly not advise anyone to fit Type ACs - but nor would I suggest that anyone should rush to 'upgrade them', unless that was being done for some other reason (e.g. new CU). I understand the theoretical issue about Type ACs but, as you may know, for at least a couple of years I have been trying hard (with no real success) to find some decent chapter and verse which helps me to quantify the 'real-world risk' (which I suspect is incredibly small).

Having said that, since I am not aware of any downsides of Type A's (other than, potentially, cost), if they can be made at not too much higher a cost than AC's, then the Type A's would make sense, even if only to address a theoretical risk. Mind you, in view of what I said about RCDs in general in my last post, I suppose that the question of the 'Type of RCD' may become rather moot!

Myself I would not choose to put one of those WiFi monitors in ...

Nor would I, not the least because there would seem to be much simpler ways of determining/estimating how much electricity a shower is using - but, as you say, that's for the OP to decide.

Kind Regards, John

 

[ebee]

John, I think we are pretty much in agreement on just about every item then.

I will just say that yes RCDs give you another chance, perhaps. But I cringe they way some folk rely on them by taking additional chances (less precautions) than they would otherwise on a non RCD circuit. That does worry me. They can be, under many circumstances, a good addtiona;l source of protection but are an "as well as" not an "instead of". The only place you do place some reliance on them is a TT system, in that case I`d rather have two in series to, notationally , reduce the risk. Either a 100mA TD upfront with a 30mA nearby has some merits even though 100mA is not considered personal protection. Or two 30mA in series, preferably in separate locations to reduce risks of "stiction".

SPD yes, protects equipment (sometimes) on a bad day so probably worthwhile.

 

[ericmark]

Think you have missed the point, I did consider an auto resetting RCD before they were not permitted for domestic, but the problem is to fit anything into a consumer unit, without making it into a distribution board, the items must comply with type testing rules, so the CU manufacture has to say they can be used.

We have seen the problems with varying bus bar heights, and cut outs, also there is the distribution of heat, so a bell transformer has to be same make as CU even when not connected to bus bars.

Not sure what the smart function is? Other than current monitoring, but can't see any BS numbers so not sure if allowed?

 

[Harry Bloomfield]

It really has never been rocket science - although perhaps surprising, the number of UK domestic deaths due to electrocution which might have been avoided by RCD protection has always been so low that there has never been scope for any 'measure' (like the installation of countless millions of RCDs) to save many lives.

I'm a definite supporter of the need for RCD's, but in certain environments, one of which is any mix of moisture and electrics, especially so any temporary supplies. I've told this story before, but I will repeat it....

I was charged with dealing with the aftermath of a totally flooded banking hall, as in - sodden walls, carpet, and water dripping down from the ceiling. I isolated all supplies, all circuits, and to enable pumps, driers and fans to be left running, I added some temporary supplies for the industrial grade, metal framed equipment. I wasn't able to source any RCD's, or RCBO's so I used several plug-in RCD's, for each appliance and placed a large notice, near the temporary outlets - saying the RCD's were not to be removed and left it to it.

Early next morning, I popped in alone, to check on progress, me already soaked from the heavy rain outside, walking into the banking hall in almost complete darkness, feeling my way to switch some temporary lights. I happened to make contact with the metal casing of one of the dehumidifiers, and was thrown across the banking hall. Once I had recovered enough, I made my way to the main switch, turned everything off, then began investigating why the case of the unit was live and why it's RCD had failed to operate.

I found the earth wire had become disconnected, water had entered the enclosure, making the metal frame live. The plug-in RCD had been removed and the unit plugged directly into the socket.

Once the clean up crew arrived on site, I was able to ask them why, despite the clear notice, someone had decided it was OK to remove an RCD. I was informed it was a semi-skilled co-worker, who had been in during my absence, who had removed it. They had been asked to investigate why the RCD was repeatedly tripping and had decided the RCD must have been faulty, rather than the equipment plugged into it, so had removed it..

I consider myself lucky, I was thrown off the live parts, by the shock - it could have turned out much worse.

 

[ebee]

Wow. Glad you survived it Harry.

I think you might have been completely justified to vent your anger to the incompetent and the supervisors.
I bet you thought of getting a pointy stick to poke them in the eye with.
I think I might have done that, I certainly would have used colourful language

 

[ericmark]

I all like RCD protection, but think missing the point, I went to the web site, and they have RCBO version, and also versions where the minimum and maxium voltage can be set, so would auto disconnect with loss of PEN. In all it seemed to have a lot of really good stuff on offer.

Some were marked CE although that's no good for UK, but no BS or EN numbers, so could use as well, but not instead of a standard MCB, RCBO.

There are versions with a mechanical reset, and marked as B32 etc, but they are double unit width, so not comparable with UK consumer units.