Why pre-screen solar installers before the interview
Two things go wrong in this trade. Somebody gets hurt on a roof or by a live direct current circuit that cannot simply be switched off, and a customer discovers their system produces a third less than they were told because a chimney shades a string every afternoon. Engineers worth hiring take both seriously. A short screen asks about safe isolation and about a system that underproduced.
What actually matters when screening Solar Installation Engineer candidates
- 01
Hands-on competence
Check hands-on volume: roof types worked (slate, pantile, standing seam, ground mount), string sizing and DC cable runs, inverter and battery commissioning (SolarEdge, Fronius, GivEnergy), plus 18th Edition and MCS experience.
- 02
Safety discipline
Probe working at height discipline: harness and anchor use, scaffold or tower sign-off (PASMA, IPAF), DC isolation before panel connection, arc flash awareness, and refusing unsafe roof or weather conditions.
- 03
Fault finding
Test diagnostic method on underperforming arrays: string voltage and insulation resistance readings, IV curve or clamp meter checks, shading and optimiser faults, earth faults, and inverter error codes traced to root cause.
- 04
Reliability and conduct
Assess conduct on customer roofs and in loft spaces: timekeeping across scheduled installs, van stock and tool control, tidy cable management, handover packs, and DNO or MCS documentation submitted on time.
Pre-screening questions to ask Solar Installation Engineer candidates
12 questions grouped by what they test. Ask the same set in every screen and score answers on a consistent scale, or send them as an async video screen and compare answers side by side.
Installations completed
3 questions01Describe your experience with solar installation and the system types you have worked on.
Listen forInstallations they led with roof types, system sizes and mounting methods described specifically.
Experience described as assisting, or system sizes and mounting types left unstated.
02What types of inverters have you worked with, and what do you prefer?
Listen forString and module-level options compared on shading, monitoring and fault finding rather than price.
Inverter choice made on cost alone, or no view on when module-level electronics are worth it.
03How familiar are you with battery storage, and have you installed any?
Listen forStorage installed with the additional electrical and fire safety requirements understood properly.
Storage claimed without the relevant qualification, or siting and ventilation not considered.
Site assessed properly
4 questions04How do you assess whether a site is suitable for an installation?
Listen forShading surveyed across the year, with roof structure, condition and fixing method all assessed.
Suitability judged from satellite imagery, or roof structure not inspected before quoting.
05Can you give an example of optimising panel placement for a site?
Listen forLayout decided from a shading analysis with string design matched to the shading pattern.
Panels placed to maximise count, or strings run across differently shaded roof planes.
06What design software are you proficient with?
Listen forDesign tools used with the output checked against site measurement rather than trusted directly.
Yield estimates produced from software without site verification, or shading input approximated.
07What experience do you have with assessing consumption before an installation?
Listen forActual consumption profile examined so the system is sized for real use rather than roof area.
Systems sized by available roof space, or consumption assumed from annual totals alone.
Height and direct current
2 questions08What safety practices do you follow when installing solar systems?
Listen forWorking at height and live direct current both addressed, with correct isolation sequence described.
Safety answered as protective equipment, or the fact that an array cannot be switched off missed.
09How do you ensure installations comply with the relevant regulations?
Listen forElectrical standards, grid connection requirements and building rules all known for the jurisdiction.
Compliance described generally, or connection notification requirements not understood.
Underperformance diagnosed
3 questions10Can you explain a time when you troubleshot a problematic installation?
Listen forUnderperformance traced systematically through shading, string faults, connections and then inverter settings.
Components replaced without diagnosis, or generation data never examined before attending.
11What is your approach to quality control during and after an installation?
Listen forTesting and commissioning documented, with generation checked against the estimate after handover.
Commissioning treated as switching on, or performance never compared with the quoted estimate.
12What maintenance do these systems need, and how do you explain that to customers?
Listen forRealistic maintenance and degradation explained upfront, with monitoring set up so faults are noticed.
Systems described as maintenance free, or no monitoring left in place for the customer.
How to score responses
Score every candidate on the same four criteria immediately after the screen. At this stage you are shortlisting for panel interviews, not making the final call.
Hands-on competence
35%5Names array sizes, mounting systems and inverter brands installed, and describes commissioning tests and G98/G99 paperwork from memory.
Safety discipline
30%5Recounts a specific job halted for wind, scaffold defect or live DC risk, and cites their isolation and lock-off sequence.
Fault finding
20%5Walks a real underperformance callout end to end, quoting meter readings and the fault found rather than guessing at symptoms.
Reliability and conduct
15%5Shows evidence of completed jobs signed off first time, clean documentation, and references from installers or homeowners.
A live array cannot simply be switched off, and a chimney can cost a third of the yield. A one-way video screen tests both.
Try it on HirevireScreening FAQ
Process basics
How long should a pre-screening round for this role take?
Ten to fifteen minutes across eight to ten questions, answered async. Enough to establish installations completed, test their site assessment, and check safety and fault finding.
What must be verified alongside the screen?
Electrical qualifications, working at height training and any scheme registration your jurisdiction requires, in full. These are legal requirements and cannot be substituted by installation experience alone.
Evaluating answers
What is the strongest signal when screening this role?
A system that underproduced and why. Engineers who follow their installations know the cause. Anyone whose systems all met their estimate has not checked the generation data afterwards.
How do I judge their safety practice?
Ask how they isolate a live array. Sound answers recognise that a panel in daylight cannot be switched off and describe the correct sequence. Anything vague here is dangerous on a roof.
Go deeper on this role
Sanat has been hiring since 2012 and watching the recruitment industry change up close ever since, and turned that screening process into Hirevire's video screening platform. LinkedIn
