Photovoltaic systems

If you’re a solar PV installer looking to buy photovoltaic panels, inverters or solar PV kits - we have everything you need. 

Follow these links to see our product range:

Solar PV panels – also called solar PV modules.

Solar PV inverters.

Mounting racks – in 6m lengths, for quicker and easier fitting on site.

We also supply solar PV cabling, components and fixings – visit our online store or ask us for details.

Our solar PV sales team is ready to help – just call 07786 184 990.



Looking for more information about solar PV?

We’ve compiled this helpful list of frequently asked questions, and included some resources you or your customers may find useful.  But if your question isn’t here, just give our technical team a call – we’ll be happy to answer.


How does solar PV work?

Solar PV (short for photovoltaic) works by converting daylight into electricity.  Solar PV panels comprise a number of solar cells, which typically contain the semi-conductor silicon. 

When the electrons in the silicon are exposed to light, they are energised into movement, and so create a direct current.  This direct current (DC) is fed into an inverter, which changes the current into alternating current, suitable for powering domestic appliances. 

Because solar PV is powered by light, not heat, the system generates electricity during daylight, whatever the weather.  Of course, the amount of electricity generated will depend on how much light the solar panels receive – so in winter this may be less than during long, bright summer days. 

It’s interesting to note that solar PV systems actually give their best output in cooler, bright conditions.  That’s because solar PV panels and inverters don’t perform well when they get too warm.  Solar PV panels have a ‘knock level’ – a loss of efficiency that starts to happen when the panels reach a certain temperature, which means their output can drop considerably.  The inverter itself may stop working if it gets too warm.  So it’s important to check the specification of the panels and inverters to find out the temperature and power tolerances.  It’s worth remembering though that the temperature range we usually experience makes the UK generally very well suited for solar PV.

If the solar PV system generates more electricity than is needed by the home at any one time, the excess can be fed back into the National Grid.  When there is a shortfall, then extra electricity can be taken from the grid to top up the supply.

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How many solar panels does the average home need?

Usually a solar PV system, or array, will comprise around 16-18 solar panels (also called modules).  But it depends on the amount of power the home needs, and the output of the panels.  Each panel has a nominal level of output (eg, 210W).  If, for example, a home needs to generate 3kW of electricity, then you would need 14 panels with an output of 210W.  If the panels only have an output of 185W, then you’ll need 16 panels.  Use the configurator in our online store to check exactly what you need.

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What’s the largest solar PV system which can be installed on a domestic property? 

The rule of thumb is not more than 16 amps per phase, which equates to a maximum of 3.68kW for a single-phase domestic installation.  Anything larger than that will need permission from the electricity distribution network operator, which is likely to involve a delay of several weeks.

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Is planning permission needed for a domestic solar PV installation?

Generally, no – in England, Wales, Scotland and Northern Ireland it would be classed as a Permitted Development.  Exceptions would be:

  • if the array is to protrude more than 200mm;
  • if the installation is for a listing building;
  • if the home is in a conservation area;
  • if the installation is to be free-standing, rather than roof mounted.

We would always advise you check with your local authority Building Control in case of any query.

Even if the installation is for a listed building, it could still be possible.  We work with a specialist solar planning consultant, who is available to advise and help get the required planning consent if need be. 

You can also visit to download their useful Quick Guide to Renewable Energy, which answers homeowners’ questions about suitability for renewable energy installations.

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What’s the best orientation for a solar PV installation?

The nearer to due south the better – and usually anywhere between south east and south west is generally preferred. 

However, some recent German research has indicated that an east-west orientation is also acceptable.  Output levels are generally more consistent over the course of the year - so there are fewer peaks and troughs than might be experienced with a south-facing installation.  An east-west installation would require an MPP (maximum power point) inverter – please ask us for more information.

Consider the angle of the roof too.  Solar PV panels work best when installed anywhere between flat and 45° - but preferably between 30° and 45°.

REB2B are happy to advise in specific cases, including visiting the site if required. 

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Does it matter if some of the roof is in shade?

It depends how much; it depends for how long; and it depends what kind of shade.  A roof that’s only partially shaded by trees for some of the day may be OK – but a roof that is significantly shaded by a building for most of the day would probably not be suitable for solar PV. 

REB2B are happy to advise in specific cases, including visiting the site if required. 

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Can any brand of solar module be installed in the UK?

Yes, as long as they are suitable for use in the UK… but not all will qualify for the UK government’s ‘feed-in tariff’.  Only panels that are approved by the Microgeneration Certification Scheme (MCS) will qualify, and they must be installed by an approved MCS installer.  All REB2B’s modules are MCS approved – click here to view our product range

Visit to find out more.

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Who can install solar PV kits?

Although anyone with the knowledge of how to do so can install a solar PV system, the installation must be supervised and approved by a registered MCS installer if it is to qualify for the UK government’s feed-in tariff.  Solar PV installations do constitute electrical work, so it is vital to ensure the work is conducted to professional standards, and that Building Regulation requirements for electrical work (Part P) and thermal containment (Part L) are adhered to.  An MCS registered installer should always be the preferred choice.

Visit to find out more.

If you’re interested in installing solar PV, and you’re not an MCS installer, why not talk to us today and see how we can support you through your MCS registration?

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What’s an Öko test?

“Öko test” is German for “eco test”.  ÖKO-TEST is a German magazine which tests and reviews a vast range of consumer products for health considerations, performance and environmental impact.  In 25 years, Öko-TEST magazine has reviewed around 100,000 products.  (The nearest equivalent in the UK is probably Which? magazine.)  Öko tests are highly respected in the industry, and manufacturers are always keen to achieve a good Öko test result.

You can find out more at

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What’s the difference between monocrystalline and polycrystalline modules?

A monocrystalline panel is typically made of a single large silicon cell.  These panels tend to look like a grid of rounded squares - take a look at the Upsolar 185M white as an example. 

Polycrystalline panels are made of many tiny silicon cells, and tend to look more geometric – the Upsolar 230P is a good example.

Monocrystalline is the older of the two technologies, and tends to be the more reliable, with panels typically having a higher efficiency level.  It is also a more expensive technology, so monocrystalline panels may cost more than polycrystalline ones.  However, solar PV technology is changing and improving constantly, and the gap between monocrystalline and polycrystalline panels is narrowing, both in terms of performance and price.

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How do I know which modules and inverters to use together?

It is vitally important to get this right.  The voltage generated by the panels must be within the tolerances for the inverter.  Inverters work at their best between certain temperatures and certain levels of voltage output from the panels.  Get the combination wrong, and the system will seriously underperform, or fail altogether. 

To help you get it right, we have devised a dimensioning tool, which you can download here.  This shows which inverters we recommend for certain panels (note how this varies depending on whereabouts in the country the installation will be). 

Also consider if the inverters will need to be mounted inside or outside.  And consider too if you may need more than one inverter, depending on the size of the system.

We’re always on hand to answer any questions and recommend specific compatible products.

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How does the UK government’s ‘feed-in tariff’ work?

The feed-in tariff is an incentive to homeowners (and business owners) to install a solar PV system.  The government has agreed to pay a sum to the owner of the installation for every unit of electricity generated.  Even if the homeowner uses the electricity to power their own home, the government will still pay them for generating the electricity.  If the homeowner sells their excess electricity back to the National Grid, the government also pays a smaller sum for each unit of electricity sold back.  So the homeowner wins financially in three ways – reduced electricity bills; money for generating their own electricity; and money for the electricity they sell. 

Feed-in tariffs are payable on installations up to 5MW.  Installations under 50kW must meet the criteria of the Microgeneration Certification Scheme (MCS).  Larger installations have a separate accreditation process, called ROO-FIT.

Visit to find out more.

For more information about feed-in tariffs, visit the Department of Energy and Climate Change website.

Remember, REB2B can support solar PV installers with the power purchase agreement. 

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What's the PV Cycle scheme?

With the lifespan of solar PV panels exceeding 25 years, it’s easy to forget about what happens when the system comes to the end of its useful life.  But for some customers it’s a very important consideration.  Thankfully, the industry has developed a scheme whereby it takes responsibility for recycling solar PV modules – and we’re delighted to say that every one of the brands we sell is part of the scheme.

PV Cycle is a voluntary, not-for-profit, industry-run scheme, founded in 2007.  Solar PV manufacturers pay to join, which allows their solar modules to be collected for recycling at the end of their life, at no cost to the customer. 

After three years of gaining momentum and commitment from solar PV manufacturers, the scheme opened its first recycling collection point in Germany in June 2010.  Since then a further 172 collection points have opened across Europe – 6 of them in the UK (the nearest to the South West are in Reading, Milton Keynes, and Chessington).

In October 2011, PV Cycle announced the scheme had collected over 1,000 tonnes of old PV panels for recycling – quite an achievement.  Because the solar PV industry in the UK is still in its early stages, the UK has only collected 2 tonnes so far (the most established solar PV market, Germany, is by far the leading recycler at the moment).  But when today’s installations come to the end of their life, it’s good to be able to reassure your customers that PV Cycle can take good care of their old solar panels – helping to ensure solar PV is an environmentally-friendly choice in more ways than one.

To find out more, visit

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How do I buy solar panels from REB2B?

Please refer to our “How to order” page.

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Other useful websites

Energy Saving Trust - buyers' guide to solar electricity panels


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12 June 13

Uk crowned Europe's largest utility-scale solar market in 2013


New figures published by Wiki-Solar reveal that the UK is Europe's strongest market for large-scale solar installations.

12 June 13


Very soon the most important pv-fair of Europe will open! A lot of you will be there and we are looking forward to meeting you

12 June 13


The anti-dumping tax on the Chinese modules is a fact.