Adding a 7kW EV charger to your property draws up to 32 amps on a dedicated circuit — roughly the same as an electric oven and hob running simultaneously. On a property with a 60-amp or 80-amp main fuse, that additional demand can push your total household draw close to capacity, particularly during peak evening hours when cooking, heating, and hot water are all active.
Smart charging and load balancing solve this problem elegantly. Rather than upgrading your main supply — which can cost thousands and involve your Distribution Network Operator — a smart charger monitors total demand and adjusts charging speed automatically. You get reliable charging without tripping your main fuse or paying for supply infrastructure you may not need.
What is smart charging?
Smart charging refers to EV chargers with connected features beyond simply delivering electricity:
Scheduled charging — set your charger to start and stop at specific times. Most Hertfordshire homeowners schedule overnight charging to benefit from off-peak tariffs, reducing charging costs by 50% or more compared to standard rates.
Remote monitoring — view charging sessions, energy consumption, and costs via a smartphone app. Useful for verifying scheduled charging is working and tracking spending over time.
Tariff integration — some smart chargers integrate with time-of-use tariffs automatically, starting charging when electricity is cheapest without manual scheduling.
Solar integration — chargers that detect surplus solar generation and charge your vehicle from self-generated electricity rather than the grid. Increasingly relevant as Hertfordshire homeowners add solar panels.
Our smart EV charging systems service specifies chargers with the smart features that add genuine value for your property and usage patterns.
What is load balancing?
Load balancing — also called load management or dynamic load balancing — monitors the total electrical demand at your property and adjusts EV charging speed to stay within safe limits.
Here is how it works in practice:
- A CT clamp (current transformer) is installed around your main incoming cable
- The charger continuously monitors total household demand via the clamp
- When demand is low — overnight, or when major appliances are off — the charger operates at full 7kW speed
- When demand rises — someone turns on the oven, shower, or heating — the charger reduces speed automatically
- Total demand never exceeds your main fuse rating
The result: your EV charges as fast as your supply allows, without ever risking a blown main fuse or supply interruption.
Load balancing is not a compromise — it is intelligent charging. Your vehicle still receives a full charge overnight; the charger simply adjusts speed during peak demand periods.
Static versus dynamic load balancing
Two approaches exist:
Static load balancing sets a fixed maximum power allocation for EV charging. If your supply allows 32 amps total and household baseline demand is 20 amps, the charger is capped at 12 amps (approximately 2.8kW). Simple and reliable, but does not adapt to changing demand.
Dynamic load balancing adjusts in real time based on actual measured demand. When household consumption drops, charging speed increases immediately. When demand rises, speed reduces. This maximises charging speed while maintaining supply protection — the approach we recommend for most Hertfordshire installations.
Dynamic load balancing is particularly valuable on properties with 60-amp main fuses, common in pre-1980s homes across St Albans, Hertford, and Watford.
When is load balancing essential?
Load balancing is strongly recommended — and sometimes essential — when:
- Your main fuse is 60 amps or below
- You have an older consumer unit with limited spare capacity
- Multiple high-demand appliances run simultaneously in the evening
- You are installing a second charger or planning to add one later
- Your property has TT earthing (common in rural Hertfordshire)
During your free site survey, we measure your supply capacity and typical demand profile to determine whether load balancing is necessary or simply beneficial.
Load balancing for workplace charging
The principles apply equally to workplace and commercial installations, where the stakes are higher:
- Multiple chargers sharing a finite commercial supply
- Building systems (HVAC, lighting, equipment) competing with charging demand
- Peak business hours coinciding with charging demand
Workplace load management typically uses a centralised controller that allocates power across all charge points dynamically. Our workplace EV charging service designs load-managed systems for businesses across Hertfordshire.
See our guide to workplace EV charging in Hertfordshire for business-specific specification advice.
Cost implications
Smart chargers with load balancing cost more than basic units — typically £200–£400 additional for the charger hardware and CT clamp installation. However, this is significantly less than the cost of a main supply upgrade, which can run to £1,500–£3,000+ and involves your Distribution Network Operator with lead times of several weeks.
For most Hertfordshire properties, smart load balancing is the most cost-effective path to safe, reliable charging.
The ongoing savings from off-peak scheduling can offset the additional hardware cost within the first year of ownership, depending on your tariff and charging frequency.
Choosing a smart charger
Not all smart chargers offer load balancing, and not all load balancing systems work the same way. Key specification points:
- Dynamic versus static — prefer dynamic load balancing for maximum charging speed
- CT clamp included — confirm the clamp and installation are included in the quotation
- App quality — scheduling and monitoring should be straightforward, not an afterthought
- OZEV approval — if you are claiming the grant, the charger must be on the approved list
Our guide to choosing a home EV charger covers charger selection in detail, and our home EV charger installation service specifies smart systems where they add value.
What load balancing does not do
It is worth clarifying what load balancing cannot achieve:
- It does not increase your main fuse rating — it works within existing capacity
- It does not guarantee full 7kW charging at all times — speed reduces during peak demand
- It does not replace the need for a properly sized dedicated charger circuit
- It does not eliminate the need for RCD protection on the charger circuit
Load balancing is one component of a properly specified installation, not a substitute for professional electrical assessment.
Repairs and maintenance
Smart chargers require occasional firmware updates and connectivity checks to maintain load balancing accuracy. Our EV charger repairs and maintenance service covers ongoing support for installed systems across Hertfordshire.
Book your site survey
Whether load balancing is essential or simply beneficial depends on your specific supply and demand profile. Book a free site survey and we will assess your Hertfordshire property, measure your supply capacity, and specify a smart charging system that protects your supply and reduces your running costs.
