There are several reasons why consumer units might need replacement. A possible reason is that the homeowner recently acquired an old property and needs to make an upgrade for the electrical systems to become compliant with the current regulations. It may also be that one of the MCBs is faulty and need replacements but the suitable replacement models are no longer available. In some cases, it might be that the entire building is being renovated, so the consumer unit is included in the renovation.
Whatever the reason for the consumer unit replacement might be, it is essential that the electrical contractor in charge has the following knowledge;
Your client does not have the right qualification:
The reason you are being hired to get the job done as an electrical contractor is that your client obviously does not have the qualification required to do the job. They may have never replaced a consumer unit previously, or even never been involved in any electrical job. Therefore, they will most likely be unaware of all the faults.
An Electrical Installation Condition Report (EICR) will clearly state that the latest regulations are met, ensuring that there are no additional faults for the contractor to clear. As a contractor, you should encourage your client to get an EICR. It is important for the client to be properly educated about the level of protection they get according to BS 7671. This will ensure that the proffered solution meets the client’s budget and expectations.
Some things to explain to the clients are:
- The general wiring regulations protect all circuits against Overload and Earth leakage.
- The definition and uses of the circuit protection devices;
- RCD: Residual Current device: This protects circuits from earth leakage.
- MCB: Mini Circuit Breaker: This protects individual circuits against overload.
- RCBO: Residual Circuit Breaker with Overload: This is an effective combination of the RCD and MCB. It protects against both earth leakages and overload.
You must be future proof.
As a contractor, one of the helpful skills to learn is flexibility. You must understand that during the operation, the client is likely to have a change of mind in terms of design, position, and specification preference. Your client may decide to go for a video door security system instead of the originally agreed audio. They may decide they want a certain switch in an opposite position from the original point chosen. If you have a very stiff plan, then these changes might affect you. This is why you need to make your project plan as flexible as possible. If your design requires a 10-way consumer unit, make the original design 12-way to accommodate changes.
At the beginning of the project, endeavor to explain to the client that the consumer unit will be functional for a considerable period, and can easily accommodate changes and additions in the circuit.
High priority circuits and circuit separation
It is important to determine the particular circuits that require special RCD considerations to properly outline a circuit protection solution suiting the client’s needs.
When you separate high priority circuits, the probability of an earth leakage occurring will be eliminated. This is why the separation process is very essential. High priority circuits include smoke detection alarms and security systems. They may also include stairwell lighting, tropical fish tanks, and swimming pool pumps. However, everyone has a different preference when it comes to high priority.
What type of consumer unit should be used?
There are several types of consumer units, and it is important to choose the right unit for the right building. This choice is dependent on several factors like the client’s budget, number of circuits present, and the types of circuits in use.
Basically, the three main models of consumer units are;
- Fully Loaded consumer unit: This unit has the least cost, making it quite popular. It has a dual RCD board with MCBs included. If you have a small building with more simplified circuits, then these are very suitable. A major limitation with these units is their limited configuration flexibility and circuit separation. Some boards have no provisions for high priority circuits.
- Main Switch Consumer Unit: Some people consider this unit as the best circuit protection unit. This unit has a circuit separation. It allows every circuit to be RCBO protected. The consumer unit itself might not be too expensive, but the installation of the RCBO makes it quite a money consuming. There are various sizes of the units from 5way to 40-way.
- High Integrity Consumer unit: The popularity of this unit is rapidly growing. It combines a dual RCD unit with a main switch consumer unit. It has about 3 neutral bars and 2 RCDs. It also has a bank of RCBOs allowing the fitting of high priority circuits.
This means standard circuits have equal residual current protection, and the high priority circuits have circuit separation.
HI units were once available for only multi-storied buildings with over 20 ways. Today, most major manufacturing companies have HI solutions with as little as 10 ways. This has brought about an increased circuit design flexibility and efficiency, at an affordable rate.
If you are getting a consumer unit upgrade, you should get an efficient one. Do reach out to us on 020 71834006 for more information or replacement of your consumer units.