jamieled Posted March 5, 2020 Share Posted March 5, 2020 We're currently getting first fix electrics completed. As part of our plan for hot water, and also to meet SAP compliance, we are planning on putting in a small-ish (~4kw) solar pv array. I was planning to mount it on the ground on a wooden frame. My original plan was to use the electrician to deal with the electrical side of it - wiring up the inverter and then into the C.U. The electrician hasn't done this before and isn't keen. He'd pointed me in the direction of a few companies, but these are the types that want to charge £4k+, and I don't think it needs to cost that much as most of the work seems to be in the panel install which I can do. I have a bit of time to figure out a plan, but there's a few things that are not quite clear: 1) Are there electricans who can do this sort of stuff, or am I likely to be stuck with one of the 'installation' type companies? 2) Our current setup is a meter and temp electrical supply in an external (10m from the house) GRP cabinet. There will be a C.U. inside the house for all its loads. I wasn't planning on moving the meter, but I guess it could be done. What's the best way of connecting the solar p.v. to the main supply? 3) What, if any wiring do I need to put in now to allow an immersion diverter to work? I will probably use an off the shelf type as I don't have time to fiddle around with a DIY version right now. cheers Jamie Link to comment Share on other sites More sharing options...
ProDave Posted March 5, 2020 Share Posted March 5, 2020 I am staggered that your electrician can't or won't do this. It is just a radial circuit from the consumer unit to the inverter, with an ac isolator switch and a generation meter. And a DC isolator switch between the inverter and the panels. If your remote meter is in a decent cubicle it could remain there, mine is about 20 metres from the house. As for the PV diverter. That will have a current clamp on one of the meter tails. Even if the meter is still in the remote cabinet, that can be fitted in the house, as long as the external meter box does not feed off to other places, just the house. If like us, the external meter box feeds to other places, then the current clamp would have to go in the outside meter box. I provisioned for that by laying a length of spare SWA telephone cable to the meter box. Before you go any further I would choose which PV diverter you are going to use. Others will have to recommend one as I made my own. You will need to register the PV with your DNO and they will need a bit of paperwork, including a schematic of the instalation. 2 Link to comment Share on other sites More sharing options...
jamieled Posted March 5, 2020 Author Share Posted March 5, 2020 Grand, thanks @ProDave. We need to feed both a shed and the treatment plant, I'm not sure whether that will be done from the external box or the CU in the house. To me it makes most sense to do it from the external box, so I may run a wire similar to yours once I work out what the immersion diverter needs. Link to comment Share on other sites More sharing options...
ProDave Posted March 5, 2020 Share Posted March 5, 2020 Find out what solar PV diverter you will be using first. I am out of touch with what is available. Link to comment Share on other sites More sharing options...
MikeSharp01 Posted March 5, 2020 Share Posted March 5, 2020 27 minutes ago, jamieled said: 1) Are there electricans who can do this sort of stuff, or am I likely to be stuck with one of the 'installation' type companies? No need to use an installation company - One upon a time this was something of a closed shop around the MSC scheme, they would only do the whole job, but these days the sands have shifted and I have had several quite reasonable, few hundred quid, quotes to certify my own work on installing and connecting the array if I do all the paper work with the DNO they will provide the MCS certificate and then we can get the export tariff. Link to comment Share on other sites More sharing options...
ProDave Posted March 5, 2020 Share Posted March 5, 2020 A quick search finds this one https://www.ebay.co.uk/itm/Solar-iBoost-Free-Hot-water-from-your-PV-Solar-Array-Immersion-controller/123863648409?_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D1%26asc%3D225114%26meid%3D29b39850189049778a4f90ca1f0dc22f%26pid%3D100005%26rk%3D10%26rkt%3D12%26mehot%3Dpf%26sd%3D282178038088%26itm%3D123863648409%26pmt%3D0%26noa%3D1%26pg%3D2047675&_trksid=p2047675.c100005.m1851 It has a wireless sensor. It would be worth digging into the specs to see what it's range is. that might save having to run a cable to the meter box. It says "The distance between the water tank and utility meter is less than 30m." so it might work for you with no extra wiring. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted March 5, 2020 Share Posted March 5, 2020 The Apollo Gem is another one with a wireless sensor: https://www.apollosolarelectric.co.uk/products/ Has a 30m to 40m indoor wireless range, according to the spec. 2 Link to comment Share on other sites More sharing options...
ragg987 Posted March 6, 2020 Share Posted March 6, 2020 4 hours ago, jamieled said: What, if any wiring do I need to put in now to allow an immersion diverter to work? Just to add also think about how many immersion heaters you want to use. On our 300l DHW I specified a lower and upper immersion. The diverter logic switches to lower heater when the upper one hits the set temperature. Gives more usable DHW this way. The upper immersion is above the main heating coil of the ASHP, so this permits a half tank of 45C below a hotter volume of 60C, which is my cut off for upper immersion. I have an Immersun diverter. Link to comment Share on other sites More sharing options...
dpmiller Posted March 6, 2020 Share Posted March 6, 2020 I went for the Iboost+ and it's not bad. Our meterbox is 15m away, behind 40mm of foiled PIR and a reflective VCL and there's no issue with signal. I picked it up used so it isn't on the latest software; this means it starts diverting at 200W or so. The latest ones are configurable between 100 and 500W I believe, to allow better integration with battery systems. Link to comment Share on other sites More sharing options...
jamieled Posted March 7, 2020 Author Share Posted March 7, 2020 Thanks all for the recommendations. Will do a bit of research into the options and go from there. Link to comment Share on other sites More sharing options...
gc100 Posted April 18, 2020 Share Posted April 18, 2020 On 06/03/2020 at 01:30, ragg987 said: Just to add also think about how many immersion heaters you want to use. On our 300l DHW I specified a lower and upper immersion. The diverter logic switches to lower heater when the upper one hits the set temperature. Gives more usable DHW this way. The upper immersion is above the main heating coil of the ASHP, so this permits a half tank of 45C below a hotter volume of 60C, which is my cut off for upper immersion. I have an Immersun diverter. Could you explain this more please? Does you hot water tank have 2 immersion units? Is the ASHP running the top immersion? or have I got the wrong end of the stick?? Link to comment Share on other sites More sharing options...
ragg987 Posted April 18, 2020 Share Posted April 18, 2020 I have a tall 300l DHW cylinder. It has 2 direct electric immersion heaters and one heating (water) coil. The coil sits in the bottom half of the cylinder, that way the ASHP can heat the full tank. The ASHP thermostat sits about 1/3 up from the bottom of the tank. The upper immersion is just above the coil. The lower immersion is near the bottom of the tank. Hope that makes sense, I have a schematic someplace if not. 1 Link to comment Share on other sites More sharing options...
Pete Posted April 18, 2020 Share Posted April 18, 2020 3 hours ago, ragg987 said: I have a tall 300l DHW cylinder. It has 2 direct electric immersion heaters and one heating (water) coil. The coil sits in the bottom half of the cylinder, that way the ASHP can heat the full tank. The ASHP thermostat sits about 1/3 up from the bottom of the tank. The upper immersion is just above the coil. The lower immersion is near the bottom of the tank. Hope that makes sense, I have a schematic someplace if not. Could you please show your schematic for us to have a look at please? TIA Link to comment Share on other sites More sharing options...
ragg987 Posted April 19, 2020 Share Posted April 19, 2020 Here you go. Page 1 is the buffer, page 2 is the DHW cylinder. DHW cylinders.pdf 1 Link to comment Share on other sites More sharing options...
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