Typical Pricing for Outsourced Electrical Design
Solar PV Design Services
- Domestic (3–10kW) from: £250
- Commercial (10–50kW) from: £500
- Large Commercial / Industrial (50kW+) from: £1,200
EV Charger Design
- Single domestic charger from: £75
- Commercial multi-point (3–10 chargers) from: £200
- Large commercial / fleet (10+ chargers) from: £500
Cable Calculations Only
- Simple circuits (1–3 circuits) from: £50
- Complex installations (multiple circuits) from: £75
Design Verification / Review
- Solar Design Verification from: £150
- House Rewire Assessment from: £200
- Second Opinion on a Contractor Quote from: £75
- Electrical Safety Consultation from: £100
- Detailed technical review from: £100
- Expert witness / dispute resolution from: £500+ (hourly)
What Affects the Price?
Project Complexity
More circuits mean higher cost. Battery storage integration typically adds £50–£100, and EV charger integration adds similar. Three-phase systems cost 20–30% more than single-phase equivalents.
Turnaround Time
- Standard (48–72 hrs): Standard pricing
- Express (24–48 hrs): +20–30%
- Rush (under 24 hrs): +50–100%
Documentation Requirements
- Basic SLD and cable calcs: Standard pricing
- Full compliance pack (G100, commissioning sheets, etc.): +£50–£100
- Detailed specifications for tender: +£100–£200
Hidden Costs to Watch For
Revisions: Most providers include 1–2 rounds of revisions free. Additional revisions: £25–£75 each.
Site visits: Most design work is done remotely from photos and plans. On-site surveys typically cost £200–£500 plus travel.
Software licensing: When outsourcing, software costs are included in the price. Hiring full-time means £2,000–£3,000/year for CAD, PVsyst, etc.
Cost Comparison: Outsourced vs Full-Time Designer
Full-Time Designer (True Annual Cost)
- Base salary: £40,000–£55,000
- Employer NI (13.8%): £5,520–£7,590
- Holiday cover (28 days): £4,400–£6,050
- Pension (3% minimum): £1,200–£1,650
- Equipment & software: £2,000–£3,000
- Office space: £2,000–£4,000
- Recruitment: £3,000–£5,000
- Training / CPD: £500–£1,500
Total: £58,620–£83,790 per year — and you're still paying during quiet periods.
Outsourced Design (Annual Cost for Typical Contractor)
10 projects/month × £200 average = £2,000/month
Annual: £24,000
Savings: £34,620–£59,790 per year
When Is Outsourcing Worth It?
Outsourcing makes sense if you:
- Do 5–20 solar projects per month (sweet spot)
- Have variable workload with busy and quiet periods
- Want to avoid £60,000–£80,000 full-time overhead
- Need BS7671 expertise you don't have in-house
- Want fast turnaround without hiring pressure
Hiring full-time makes sense if you:
- Do 30+ projects per month consistently
- Need daily on-site design support
- Have very specialised or unique requirements
- Want complete in-house control
Questions to Ask When Getting Quotes
- What’s included? (SLD, calcs, G100, revisions?)
- What’s the turnaround time?
- Are you BS7671:2018 certified?
- Do you guarantee compliance?
- What happens if the DNO rejects the design?
- Can I see sample deliverables?
- What’s your revision policy?