Unfortunately the Northern Territory comms-hubs don't have an external aerial option.

The theory is that 423MHz is sufficiently low that it can penetrate walls.
But that theory doesn't make allowances for signal blockage or absorption by nearby objects.

It's possible that relocating the meter-position within the house solves the problem.
But installers seem to think they should only attempt the existing position, with 'tails' as short as possible.

If this were me, before fixing the new ESME and Comms Hub to the wall, I'd temporarily run it from a piece of electrical flex plugged into a wall socket.
It could then be moved around in 3D space to see if the signal was better close by, possibly in an external box.
Perhaps they won't try that because it's not stipulated in the training manuals, and would therefore require ingenuity.

@transparent Everything in life nowadays seems to run to a box ticking schedule. If there is a problem, find the right precedure sheet, work through ticking all the boxes and the job is done. Thats fine when the problem is a routine issue, but the minute something crops up that isn't a standard problem there is no flexibility or room for initiative in the system to do anything that isn't on the list of procedures. 🤨 

I've been thinking about the surge issue. I haven't yet added up the power used by all devices in the house but as well as the ASHP there are other items that probably have high surge demands - under sink water heater, induction hob, wordworking equipment such as a bench router and planter thicknesser.

Do I have to get an inverter and battery capacity that will deal with the maximum likely surge or can I safely assume that if, at any point the surge is to much for the inverter it will simply draw the extra power from the grid?

Thanks again for your copious posts.

Posted by: @homonid

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Do I have to get an inverter and battery capacity that will deal with the maximum likely surge or can I safely assume that if, at any point the surge is to much for the inverter it will simply draw the extra power from the grid?

I'm assuming that we're now discussing the SunSynk inverters and the diagrams I posted on the previous page here.

The Loads that are connected to the "On Grid Home Load" will draw power from the grid if the inverter is unable to supply them.

Those that are connected to the Off Grid / Backup port must be rated within the maximum output specified for that port.
Thus, if the inverter is a 5kW unit - demand on the Off-grid connection must be within the 5kW limit.
When two 5kW inverters are operating in parallel, then the limit is obviously 10kW etc.

The reason I'm suggesting you consider installing a SunSynk inverter is because it gives you versatility to use it in different ways.

I too have house loads which might take my inverters beyond their operational capacity if they were all connected to run off-grid.
Those are therefore connected to the grid side of the inverters, and will be unable to work during a power-cut.

Posted by: @homonid

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I haven't yet added up the power used by all devices in the house but as well as the ASHP there are other items that probably have high surge demands

When you send a G99 Application to your DNO (Electricity North West), the sum of all possible loads in the house is one of the parameters you are required to state.

Usually an electrician goes around and quickly totals up all your directly connected appliances, then adds in the rating of the MCB which runs the lighting circuit(s).
But you don't need to have an electrician. Any householder can apply for G99 and it's free to do so.

It would be unreasonable to add together the total load of all your machine tools.
You would never expect to operate a planer/thicknesser and a bench router simultaneously for example!

I'm in a similar situation. I have 14 mains driven workshop tools.

If the sum of all the loads which could operate simultaneously comes to more than 60A current, then it's likely that your DNO will want to upgrade your supply to 3-phase.
That may or may not be a good idea.
It may or may not be a chargeable upgrade.

Do the maths first, then discuss here if you believe you might exceed 60A.

There are multiple solutions.

@homonid answering the simplest aspect of your questions only. If you draw peak currents which could be higher than the inverter output then your top-up peak supply comes from the grid if you’re on the grid tied option. I find the grid is very useful in this regard!

If you’re on the off-grid output then depending on the inverter design it could blow a trip, kill the output stage or in the least likely option limit the current (and hence probably the voltage in the output stage). I imagine that a trip is the more common design. 

Yes @judith is right that you will in any case need to be using fuses and trips for the various connections to your inverter(s).

Fortuitously this is another subject which I've investigated thoroughly.
You will be receiving advice here on the forum when you actually get to the stage of wiring things together.

If you want to know what happens when things go wrong... then I'm your man 😉 

Yes, that's a 125A MCB which was between an inverter and a 52v battery.

@transparent and @judith thanks for your recent replies. I must consider now what I want to achieve. With much rennovation still to do and a possible extension to follow, the electrical consumption of the house when all this is finished is hard to predict. I am minded to go for something simple in the short term to give me cheap heating for the next few years and then reassess the backup needs when the renovatioin project is nearer completion.

I'm unsure whether that means you are intending to start by having a heat-pump which runs direct from the grid,

or whether you want to limit the size of inverter and battery to handle solely the heat-pump. Thus you might increase the inverter/battery to operate the rest of the house at some future date.

Either way, I suggest that you fit dedicated LED light-fittings rather than try to use LED 'bulbs' on 240v AC.

LED bulbs have great difficulty dissipating the heat from the internal electronics. This means that they fail and require replacement.
Check those at B&Q, for example, The lifetime is marked on the packaging.

Dedicated LED luminaires are available, which have lots of heat-sink capabilities through the casing.
They either run off 240v mains, or low-voltage DC. Both could last 10yrs+

I use lighting at 24v DC, which means it can either be driven from a single power supply, or else connected to a battery (at a later date).

The days of LED lighting only being a single-point source are long gone.
They can now offer all-around illumination, shadow-free.

That is an interesting thought, low voltage LED lighting. I have been disappointed by the short life of LED bulbs. The old filament bulbs could last for a decade or more, but already a number of my LED bulbs have started flickering to the point of being a nuisance after only 18 or 24 months! They are not cheap.

@transparent   I know you’ve posted on the forums on several occasions about the north/south divide regarding smart meters. It’s now becoming a news item:

https://www.bbc.co.uk/news/articles/cq52382zd1no

It’s interesting to read that Octopus appear to be prepared to break the rules. 

Yes, I'd seen that trailer for tonight's Panoroma @ianmk13  and I'm sure it will be of interest to @homonid too

Comments here about Smart Meters and the Panorama programme have now been moved to a new topic on Smart Meter connectivity and features.

@homonid - if you'd like me to advise of running wiring for DC lighting then let's put that in a new topic.

I can provide you with lists of suppliers and photos of what I've successfully implemented.

Note, in particular, that you won't require an electrician for this.
Anything you install below 75v doesn't need Part-P certification.

@homonid we went the simple route when refurbishing the house 15years ago in using mains LED lights (in down lighters) and compact fluorescents elsewhere.
We’ve changed to all LED since. But yes failures are irritating. It’s not the actual light emitting chips that die but the very cheap control electronics which is a real waste. So using DC means simpler electronics and they should last longer. 
Of our first batch of 10 GU4s 3 died in the first 4 months and the rest lasted well over 2 years thus satisfying Philips’ claim of 1 year life which is always the average of a population. This was much better than the halogens they replaced.

If we re-wired again we might choose to go DC in some rooms but no plans at all.