As a consumer it's very hard to know a good installer from a bad one, possibly until it's too late and with disasterous results. As an electrical company with qualified solar PV experts we have a depth of knowledge other companies don't. Why use a double glazing firm or front company employing subcontractors when with Dorset Solar Power you are employing qualified tradesmen, where the director of the company will actually be working on your property!

As well as installing our own photovoltaic systems we also act as a subcontractor putting in the electrical installations for other solar companies. I assumed that everyone worked to the same high standards as we do, how wrong I was! here are a few of the things I have picked up on in my experience and things for you to look out for when choosing an installer.

INSTALLATION TIME

Many contractors will put up a complete installation in less than a day. we don't. We take pride in the fact that an installation will typically take us 2 days, because we take our time and do the job properly. I have seen panels mounted on a roof in 2 hours, but the panels faces were scratched, dropping the output of the whole array, the panels wern't straight, the roof was damaged and it's integrity compromised.

 PANELS

Panels are panels right? wrong! At Dorset Solar Power we only use quality panels from manufacturers with a long history in the business. I had some delivered the other day, here's what the driver said

'nice panels those Samsung, you can see they're good, we never have to take any back. some of the panels out there, we deliver them and then a few days later we have to come and take half of them back 'cos they aren't working'

And thats at point of delivery, how about after 10 years on your roof? we aren't allied to any particular manufacturer. we will select panels from a manufacturer that best suits your budget, roof size and personal choice, ensuring you get the best return on your investment.

INVERTERS

The inverter is a crucial part of the installation. thats why we only use the latest models from companies like SMA, Aurora and Froneous. Even in those companies some of the models are older and less efficient than the newer ones, we only use the latest and most efficient.

It is crucial that the inverter is sizes correctly for the array. The quoted output of an array is it's output under factory test conditions, not in the real world. An inverter needs to be working as close to it's maximum as possible for as much of the time as possible so on a 4kW system you would use and inverter such as the Power one 3.6. Companies that don't understand this important fact may specify an incorrect inverter, like a 4kW inverter for a 4kW system. Different inverters also have different voltage ranges and I have even seen systems so missmatched that the array doesn't generate enough voltage for the inverter to actually start up.

At Dorset Solar Power we carefully assess the most appropriate inverter for your installation, we then confirm our choice with the technical experts at our suppliers. To date they have always agreed with our decision!

MOUNTING SYSTEM

This is what holds the whole array onto your roof, so is also a crucial element. we general use the K2 mounting system but may use others depending on the requirement of the system. The rails are fixed to the roof joists by sturdy brackets fixed using specialised roofing screws. Some installers fix the rails to the roof battens. I cannot comprehend how a roof batten can possibly be strong enough to cope with the potential wind lift charateristics of a solar system. Although the BRE windlift calculation allows us to space brackets over 1.2m appart we always aim for at least one every meter. I have seen brackets spaced more than 2 meters appart, totally against the regulations. lead is expensive and this process takes time. Cost and expense a subcontractor, or installation firm, may not be willing to carry.

ROOF PENETRATION

It is a requirement of the regulations that the cables are routed through the roof in a way that maintains the integrity of the roof and will not lead to the cables being damaged. many companies simply thread the cables under the tiles. this is unacceptable as over time the cables will chaffe and wear through. Here at Dorset Solar Power we use a specialised cable entry system, the SolarDek, which protects the cables and keeps your roof watertight. to get through the roof felt I have seen companies just make a hole in the felting. this is unacceptable. the hole will tear over time, and the felt is the main waterproofing for your roof. We seek out where the roofers have placed an overlap in the layers of felt and bring the cables in there, keping your roof to the same level of protection as it was before we started.

CABLE MANAGEMENT

It is a requirement of the regulations that cables are tied up so they won't chaffe on the roof, but often I see cables lying loose on the roof. We always aim to ensure that cables are secured so they won't blow about in the wind.

CABLE SIZING

Even a 4kW solar system only generates around 16amps. A 2.5mm cable is sufficient for 16 amps so many firms, who use electricians for their installations without our level of knnowledge and expertise in solar systems, will only use 2.5mm . However, solar systems are very vulnerable to voltage drop and it is essential the installer understands the theory behind this and calculates the cable size correctly. For Example a 4kW system using an SMA 4000TL actually needs a 6mm cable. Many installers either don't understand this or don't want to use the correct size cable for cost reasons. At Dorset Solar Power we do our own calculations, but also check the inverter manufacturers data, to ensure your system is always connected with the optimum sized cable.

Many systems now also need a seperate earth, in 10mm cable.At 1.35 per metre installing this cable is costly and time consuming, so many don't bother, but this makes your system inherently unsafe and again breaches the regulations.

Heres a quote from a solar installer

'we run everything in 2.5mm cable using Kaco inverters and never earth the array or the inverter'

Scary!!

Your investing a lot of money in your solar system, we respect that and always install to the highest possible standard.  We are probably more competitively priced than most others like for like and you are assured of a quality installation that will last for years.

why take the risk with anyone else?