Now offering free design health checks

Expert Electrical Design.
No Full-Time Overhead.

On-demand solar PV design, cable calculations, and BS7671 compliance support for installers, businesses, and homeowners. 20 years of experience. 24–96 hour turnaround.

⚡ 24–96hr Turnaround
Recent Deliverables
BS7671 Compliant
☀️
12kW Solar PV Design Pack
SLD, cable calcs, G100 report
✓ Delivered
🔌
Commercial EV Charger Design
Load analysis, DB schedule
✓ Delivered
📋
Cable Sizing Verification
Voltage drop, fault loop
In Progress
🏠
Rewire Assessment Report
Consumer unit upgrade plan
Queued
20 Years
Industry Experience
📐
BS7671:2018
Fully Compliant Designs
💷
Fixed Pricing
No Surprises, No Retainer Required
🕐
24–96 Hours
Standard Turnaround

Design support for every client type.

Whether you're an installer who needs extra design capacity, a business planning an electrical upgrade, or a homeowner wanting independent advice — we've got you covered.

Three steps. No complexity.

From brief to delivery in as little as 24 hours. No long contracts, no retainer required.

1

Send Your Brief

Upload your design files, site details, or project brief via email or our contact form. Tell us what you need.

2

We Design & Review

Our experienced designer produces BS7671-compliant designs, calculations, and documentation. Most quotes confirmed within 2 hours.

3

You Install With Confidence

Receive installation-ready drawings and documentation. Revisions included. You focus on the job, we handle the paperwork.

Stop paying for empty chairs.

A full-time electrical designer costs far more than their salary. With ZESTEC, you only pay for designs you actually need.

Full-Time Designer
£74,300+
per year (true cost)
  • £50,000 base salary
  • £6,900 employer NI (13.8%)
  • £5,400 holiday cover (28 days)
  • £2,000+ sick leave
  • £2,000+ equipment & software
  • £5,000+ recruitment costs
  • Still paying during quiet periods
VS
ZESTEC On-Demand
From £500
per month / or pay per project
  • Scale up for large projects instantly
  • Scale down during quiet periods
  • No recruitment delays
  • Expert designer from day one
  • BS7671:2018 compliant designs
  • Cancel anytime — 30 days' notice
  • Only pay for work you need
⚡ Limited Availability

Free Design Health Check

Send us an existing solar PV design or electrical plan, and we'll review it for BS7671 compliance issues, sizing errors, and optimisation opportunities — completely free.

  • Branded 1-page compliance report
  • Traffic-light score (Red / Amber / Green)
  • 3–5 specific recommendations
  • Delivered within 5 working days
  • No obligation, no follow-up pressure
Request Your Free Health Check →
Design Health Check — Sample
System Size8.2 kW Domestic PV
Cable Sizing● Pass
Voltage Drop● Review
Earthing● Pass
SPD Compliance● Issue
Overall Score● Amber — 2 issues found
SAMPLE REPORT

Trusted by contractors and homeowners.

★★★★★
"We needed cable calcs for a tricky commercial solar job and ZESTEC turned them around in 48 hours. Spot on, installation-ready. Saved us from hiring a full-time designer we don't need year-round."
JD
James D.
Solar Installer, Bristol
★★★★★
"Got a second opinion on our solar quote before committing. They found the cable run was undersized for our property. That one review saved us thousands in potential rework. Highly recommend."
SR
Sarah R.
Homeowner, Cardiff
★★★★★
"We use ZESTEC as our overflow design resource. When we're stretched, they pick up the slack without any drop in quality. It's like having an extra designer on call. The retainer model works perfectly."
MP
Mark P.
Electrical Contractor, London
★★★★★
"We were having an extension done and the builders were installing the solar PV system. We asked ZESTEC for a Free Design Health Check and they found that our Solar Battery would drain whenever we plugged the EV into charge based on the design."
KT
Karen T.
Homeowner, Kent

Ready to outsource your design work?

Book a free 15-minute call to discuss your project — or request your free design health check today.