Q&As
Need an electrician in Waltham Forest? Get in touch with ZJ Electrical Services today! We’re your local experts, ready to assist with all your electrical needs. On this page, you can find answers to some of the most frequently asked questions.
Get in Touch with ZJ Electrical Services
Get in touch with ZJ Electrical Services to discuss your electrical requirements. We provide professional domestic and commercial electrical services across Leyton, Walthamstow, Leytonstone and surrounding East London areas. Whether you’re planning a rewire, consumer unit upgrade, EICR, lighting project, EV charger installation or commercial electrical work, send us the details and we’ll provide clear advice and a quotation where appropriate.
Our Location
Business Hours
Normal site work: primarily weekdays.
Weekend or out-of-hours attendance for commercial projects can be discussed and agreed in advance. Phone and email enquiries can still be sent outside normal site-working hours.
Frequently Asked Questions
Why do I need a consumer unit upgrade?
You may need a consumer unit upgrade if your current unit is outdated, lacks RCD protection, has insufficient capacity for your electrical needs, shows signs of damage, or doesn’t comply with current regulations. Modern consumer units offer better safety features and are required to meet current electrical standards.
How many smoke alarms do I need?
The number and type of alarms depend on the property, its layout and the applicable requirements. Escape routes such as halls and landings normally require suitable smoke detection, while kitchens are generally better protected by a heat alarm to reduce nuisance alarms from normal cooking. Where multiple alarms form part of the system, interconnection allows all alarms to sound when one detects a fire.
Do you carry out electrical work at weekends?
Weekend appointments are not part of our normal site-working schedule. Where a commercial project genuinely requires weekend or out-of-hours attendance, this can be discussed and agreed in advance. Phone and email enquiries can still be sent outside normal site-working hours.
Can I upgrade my light switch to a dimmer?
Often, yes. The existing lighting circuit must be suitable and the dimmer needs to be compatible with the lamps or LED drivers being used. Some LED fittings require a specific type of dimmer, and incompatible combinations can cause flickering, buzzing or poor dimming performance.
What is EIC?
An EIC (Electrical Installation Certificate) is documentation provided after new electrical installations or major rewiring work. It confirms that the new installation complies with BS7671 wiring regulations and has passed the required tests for safety and functionality.
What is a 5A socket?
It’s a socket used for lights only.
What is EICR?
An EICr (Electrical Installation Condition Report) is a detailed assessment of the condition of an existing electrical installation. It identifies any damage, deterioration, defects, or dangerous conditions in your electrical system. This inspection is conducted by a qualified electrician.
When do I need an EICR done?
There is no single inspection interval that applies to every commercial electrical installation. The appropriate interval depends on the type of premises, use of the installation, environmental conditions, maintenance and the findings of the previous inspection. The EICR states the recommended date for the next periodic inspection.
Rented residential properties are subject to separate requirements, which should not be confused with the inspection intervals for commercial premises.
What is RCD?
An RCD (Residual Current Device) is a safety device that quickly disconnects the electricity supply when it detects an imbalance in the electrical current, which could indicate a fault or current leakage. RCDs provide protection against electric shock and are designed to prevent fatal electric shocks.
What is RCBO?
An RCBO (Residual Current Breaker with Overcurrent Protection) combines the functions of an RCD and a circuit breaker. It protects against both residual current faults (electric shock) and overcurrent conditions (overloads and short circuits) in a single device, offering enhanced protection for individual circuits.
Do I need a metal consumer unit?
Modern domestic consumer units are generally manufactured with non-combustible enclosures, most commonly steel, to help contain fire within the enclosure if a fault occurs. Current installations and alterations should be assessed against the applicable requirements of BS 7671.
How can I reduce my electricity bill?
To reduce your electricity bill:
- Switch to LED lighting
- Use energy-efficient appliances
- Unplug devices when not in use
- Install a smart meter to monitor usage
- Add insulation to reduce heating/cooling needs
- Use timers or smart controls for heating systems
- Maintain your electrical systems for optimal efficiency
Can I have underfloor heating installed?
Yes, underfloor heating can be installed in most homes. There are two main types: electric (easier to install, especially in existing homes) and water-based (more efficient for larger areas). Installation is possible during new construction or renovation, though retrofitting may require raising floor levels or removing existing flooring.
Can I have a car charger installed?
Yes, home EV chargers can be installed for most properties with off-street parking. Installation requires a dedicated circuit from your consumer unit and sufficient electrical capacity. A qualified electrician will assess your property’s suitability and may recommend upgrades to your electrical supply if needed.
Which car charger should I get installed - Zappi or Hypervolt? Which app and customer service is better?
Both Zappi and Hypervolt offer quality home EV charging solutions:
Zappi offers excellent integration with solar panels and home energy systems, allowing you to charge your vehicle using excess solar energy. Their app provides comprehensive energy monitoring and their customer service is known for being knowledgeable about renewable energy integration.
Hypervolt offers a sleek design and user-friendly experience with competitive pricing. Their app is intuitive and provides detailed charging analytics, while their customer service typically offers quick response times.
The best choice depends on your specific needs—Zappi is ideal if you have or plan to install solar panels, while Hypervolt may be better if you prioritize a streamlined user experience and design.
What is an SPD?
SPD stands for Surge Protective Device. An SPD is a component designed to protect electrical systems and equipment against voltage spikes, also known as transient overvoltages or surges.
Key features and functions of SPDs include:
Diverting excess voltage: SPDs detect voltage surges and divert the excess current to ground, protecting downstream equipment.
Response time: They respond extremely quickly (within nanoseconds) to voltage spikes.
Classification: SPDs are typically categorized into different types or classes (Type 1, 2, and 3) based on their installation location and protection level.
Protection against: Lightning strikes, switching operations in the power grid, and other causes of transient overvoltages.
Common applications: Used in electrical distribution panels, power supplies, communication systems, and to protect sensitive electronic equipment.
SPDs are essential components in comprehensive electrical protection systems, particularly in areas prone to lightning or in facilities with sensitive electronic equipment.
EV charging options compared
Not every electrical outlet is intended to be a long-term EV charging solution. The correct option depends on the vehicle, charging equipment, electrical supply and how the installation will be used.
Standard 13A socket
- Charging use
- Occasional or low-rate charging using compatible portable EV charging equipment.
- Typical single-phase charging rate
- Usually around 2–2.3 kW with compatible portable charging equipment.
- Dedicated circuit
- Strongly preferred for regular EV charging; existing general-purpose sockets should not simply be assumed suitable.
- App / smart control
- Usually limited unless provided by the portable EV charging equipment itself.
- Load management
- Normally no, unless specifically provided by the connected charging equipment.
- Open-PEN protection
- Not provided by a standard socket itself. Any required EV charging protection must be provided by the charging equipment and installation design.
- Access control / locking
- Normally no.
- Energy monitoring
- Normally no, unless provided by the portable charging equipment.
- Best suited to
- Occasional / slower charging where the installation has been assessed as suitable.
Industrial / Commando socket
- Charging use
- Can provide a more robust dedicated connection when used with compatible EV charging equipment and a correctly designed circuit.
- Typical single-phase charging rate
- Depends on socket rating and charging equipment; commonly higher than a standard 13A outlet.
- Dedicated circuit
- Yes — normally installed as a dedicated correctly protected circuit.
- App / smart control
- Depends on the EV charging equipment connected to the socket.
- Load management
- Depends on the connected charging equipment; not provided by the socket itself.
- Open-PEN protection
- Not provided by the socket itself. Required EV charging protection must be provided by the charging equipment and installation design.
- Access control / locking
- Usually limited unless provided by the connected charging equipment.
- Energy monitoring
- Depends on the connected charging equipment.
- Best suited to
- Specialist or temporary arrangements where correctly designed for EV charging.
Dedicated EV charger
- Charging use
- Purpose-built for regular EV charging, with dedicated protection and controls designed around the vehicle and electrical installation.
- Typical single-phase charging rate
- Typically up to 7.4 kW on a 32A single-phase supply, where the available supply capacity allows.
- Dedicated circuit
- Yes — normally installed on its own correctly designed and protected circuit.
- App / smart control
- Commonly available. Depending on the charger, the app can provide charging schedules, start/stop control, charging history, energy usage and status notifications.
- Load management
- Available on many chargers. Dynamic load management can reduce the charging rate when the property is using more electricity, helping prevent the incoming supply from being overloaded.
- Open-PEN protection
- Many modern UK EV chargers include built-in open-PEN protection. Where it is not built into the charger, suitable external protection must be provided as required by the installation design.
- Access control / locking
- Many chargers can be locked or disabled through the app, RFID or another access-control method to help prevent unauthorised charging.
- Energy monitoring
- Commonly available through the charger or app, allowing the user to view charging consumption and history.
- Best suited to
- Regular home or workplace EV charging where faster charging, smart control, electrical protection and convenient everyday use are required.
EV charging circuits require assessment of the existing supply, earthing arrangement, protective devices, cable route and charging equipment. The most appropriate solution depends on the individual installation.
MCB, RCD, RCBO and AFDD — what is the difference?
MCB
- Main purpose
- Protects against overcurrent, including overload and short circuit.
- Protects against overload / short circuit
- Yes
- Residual-current protection
- No
- Typical use
- Circuit overcurrent protection.
- When is this required?
- Overcurrent protection is required for electrical circuits. An MCB is one common way of providing this where residual-current protection is either provided separately or is not required for that circuit. An RCBO may be used instead where both functions are needed in one device.
RCD
- Main purpose
- Provides additional protection by detecting residual current / earth leakage.
- Protects against overload / short circuit
- No
- Residual-current protection
- Yes
- Typical use
- Protecting multiple circuits or providing additional residual-current protection depending on the installation design.
- When is this required?
- RCD protection is required in a number of situations under BS 7671. Common examples include additional protection for socket-outlets rated up to 32A, mobile equipment for outdoor use, domestic lighting circuits and other circuits where the wiring method, earthing arrangement or installation conditions require it.
RCBO
- Main purpose
- Combines overcurrent protection and residual-current protection for an individual circuit.
- Protects against overload / short circuit
- Yes
- Residual-current protection
- Yes
- Typical use
- Individual circuit protection with both overcurrent and RCD functions.
- When is this required?
- An RCBO is used where a circuit requires both overcurrent protection and residual-current protection. It is commonly selected for individual final circuits because it provides both functions without relying on one shared RCD for several circuits.
AFDD
- Main purpose
- Detects characteristics associated with dangerous electrical arcing.
- Protects against overload / short circuit
- Not its primary function; normally used alongside or incorporated with appropriate circuit protection.
- Residual-current protection
- Not by itself unless incorporated into a combined device.
- Typical use
- Used where required or appropriate to reduce the risk associated with arc faults.
- When is this required?
- AFDDs are required on certain final circuits where BS 7671 specifically calls for arc-fault protection, and may also be selected where the fire risk justifies additional protection. The exact requirement depends on the type of premises, circuit and current edition of BS 7671.
Protective-device selection must be based on the circuit design, earthing arrangement, installation conditions and current BS 7671 requirements. One device cannot always be substituted directly for another.
EIC, Minor Works, EICR and Building Regulations certificates
EIC
- What it is
- Electrical Installation Certificate.
- Normally used for
- New electrical installations, new circuits and work requiring full installation certification.
- Is it a condition report?
- No
- Does it replace electrical certification?
- It is electrical certification.
Minor Electrical Installation Works Certificate
- What it is
- Certificate for qualifying minor additions or alterations to an existing installation.
- Normally used for
- Minor additions or alterations that do not include the provision of a new circuit.
- Is it a condition report?
- No
- Does it replace electrical certification?
- It is electrical certification for the relevant minor work.
EICR
- What it is
- Electrical Installation Condition Report.
- Normally used for
- Assessment of the condition and safety of an existing electrical installation.
- Is it a condition report?
- Yes
- Does it replace electrical certification?
- No — it reports on an existing installation rather than certifying new installation work.
Building Regulations Compliance Certificate
- What it is
- Confirmation of compliance with applicable Building Regulations following qualifying notifiable electrical work.
- Normally used for
- Notifiable electrical work where certification is provided through the applicable competent-person / Building Regulations process.
- Is it a condition report?
- No
- Does it replace electrical certification?
- No — it is separate from the EIC or Minor Works certificate.
Depending on the work carried out, customers may receive more than one document. Building Regulations notification and electrical certification serve different purposes.