Additional 6.5kW battery on order
@allyfish - what's the function of the two black rotary isolators at the top?
Have you had that DC MCB installed yet?
Save energy... recycle electrons!
- @transparent black isolators are DC solar PV isolators, two strings, one 4 panel, one 5 panel. I await the DC MCB from L R Renewables by Mail and a date when they will install….
That's interesting @allyfish.
I'm puzzled how a 'knife switch' mechanism can be used effectively with high-voltage DC.
When the circuit is broken by rotating the disc, I would expect the resulting arc to damage the edge of the blade.
Any chance of a close-up photo so we can see the manufacturer and model number of those rotary switches?
For others who are following this, and would like a bit more technical insight...
A typical solar array of rooftop panels in series will be supplying the string inverter with a voltage between 150-500v, with a current of less than 20A.
There are DC-rated MCB-style trips which can be used to handle these voltages.
They have a series of plates arranged as a ladder-network which dissipate the arc.
Such a DC trip uses a pair of magnets either side of the contacts to pull the arc into the ladder when the contacts open.
That's why a DC trip is marked with + and - symbols which tell you which way around it must be connected.
There is no 'standard' for this.
You have to look at each unit to check the polarity.
I do have a rotary isolator on the input to the inverters to comply with the safety guidance, but it is preceded by a DC-trip and a pair of fuses.
The trip is opened first, before I turn the isolator.
Save energy... recycle electrons!
@transparent they are Craig and Derricott EPV252 25A 2 pole rotary isolators. Designed for DC voltage and Solar PV isolation, 25A @ 800V. https://craigandderricott.co.uk/product/photovoltaic-pv-enclosed-switchgear/
That's neat.
And good to see that Messrs Craig and Derricott is a UK company, based in Walsall. 😎
Save energy... recycle electrons!
- 22 Forums
- 2,055 Topics
- 44.8 K Posts
- 53 Online
- 3,290 Members
Join Us!
Trusted Installers
Struggling to find a reliable heat pump installer? A poor installation can lead to inefficiencies and high running costs. We now connect homeowners with top-rated installers who deliver quality work and excellent service.
✅ Verified, trusted & experienced installers
✅ Nationwide coverage expanding
✅ Special offers available
Latest Posts
-
RE: Is your heat pump insured?
But would you need to let your insurance know you had j...
By Johnmo , 3 minutes ago
-
@johnd welcome to the forums. First time I've ever hear...
By Mars , 24 minutes ago
-
RE: IVT Greenline high pressure switch and electrical cassette errors
The temperature diff remains fairly low during operatio...
By tdudgeon , 2 hours ago
-
Win a 6-panel PV courtesy of egg and Renewable Heating Hub
Our epic giveaway just went live! Want to win a 6-pan...
By Mars , 13 hours ago
-
RE: Yes, the "zoning with ASHP" topic again...
James, thanks again for your thoughtful and persistent ...
By HarryRea , 13 hours ago
-
RE: Getting the best out of a heat pump - is Homely a possible answer?
Isn't that the whole point of homely - it does that fun...
By Johnmo , 15 hours ago
-
RE: Is this normal? Click of the DHW returning to space heating
So the Lone Ranger returned today! Even though we thoro...
By Grantmethestrength , 16 hours ago
-
RE: How To Balance Radiators & the Role of the Lockshield Valve: A Homeowner's Guide
@jamespa So settings to date are as follows for now. ...
By Alfapat , 16 hours ago
-
RE: Vaillant & OVO partner up to offer Heat Pump Plus
Hopefully iv done the right thing today by signing up t...
By Westkent , 17 hours ago
-
RE: Battery sizing - How low can you go!
My own experience with connecting four batteries to thr...
By Transparent , 1 day ago
-
RE: Plate heat exchanger considerations
Work on 2-3 percent per degree. This is a reasonable e...
By JamesPa , 1 day ago
-
RE: Advice for ground source heat pump in new build with PV and batteries
The useful bit is the bit that specifies the heat loss ...
By JamesPa , 1 day ago
-
RE: Volumisers in Heat Pump Systems: Does Placement Matter?
You’re absolutely right that during defrost the refrige...
By Mars , 2 days ago
-
@editor thanks Mars that’s the same table I found in th...
By Gary , 2 days ago
-
RE: Tariff and charging strategy advice please
They haven't asked me to prove that I have an EV (I do)...
By JamesPa , 2 days ago
-
RE: Solar Power Output – Let’s Compare Generation Figures
Took a while to find on the OFGEN site: ”The FIT sche...
By AgentGeorge , 2 days ago
-
RE: why solar diverters for HW instead of the heat pump?
For me there are few factors why you may want to heat w...
By Johnmo , 2 days ago
-
RE: Hydronic plinth heaters and ASHPs
@editor yes I think so. It will be a while until I get ...
By benson , 2 days ago
-
RE: Aira Heat Pump: Stylish Scandinavian Heating
I’m an Aira customer with a 6kW Outdoor Unit in a small...
By KevinPotts , 3 days ago