ADU Electrical Service Panel: Essential Boost for Your ADU

All experts, builders and homeowners point out that the accessory dwelling unit is a completely independent living space. However, how can we measure this independence? One of the indicators is the fact that during the construction of accessory dwelling units, specialists equip individual HVAC systems, as well as electrical wiring for these projects. The latter component plays a crucial role because the installation of the electrical service sub-panel radically changes the electricity management system throughout your property.

If you are thinking about installing an electrical panel in ADU, then this review is for you, because today we will tell you whether it is necessary for a new ADU project or not, how much does an electrical service upgrade cost, why you can not do without the help of a licensed electrician in this matter, and also introduce the basic terminology of electricity to those for whom this is a new world.

ADU Electrical Service Meter: 3 Basic Questions

Within the construction process of a new accessory structure, there is always a question of providing a living space with light, especially if your professional activity has a direct connection to the need for bright lighting. Most often, property owners ask three questions: whether it is necessary to install a separate electrical panel for the ADU, what price tag this service has, and what will await the homeowner if he ignores this aspect of the building process. Let’s answer each of these questions.

Separate electrical service panel for ADU: possible or not?

In the list of local regulations, we can easily find the answer to this question, namely, that the installation of a separate electrical service panel in the ADU is a prerequisite all over California. However, the main nuance lies in its location. If we are talking about an attached ADU or unit that stands no further than 150 ft. from the main house, then you need to install the new meter next to the existing panel in the primary residence. If the ADU stands at a distance of more than 150 ft., then grouping is not a strict requirement, and you can install a separate meter in a new ADU project.

ADU electric panels: all about costs

We identify two fundamental factors that have a direct impact on the price tag of installing a new panel in the accessory dwelling unit. First, the quality of the existing electrical wiring. For example, if you are implementing a garage conversion project and the old garage already has good wiring, then the price will be significantly lower. Secondly, if you connect the ADU sub-panel to the primary service panel in the house, it will also cost less than installing a separate meter. In general, the average price for such a service with the installation of all necessary appliances is about $10000-$12000.

ADU electrical panel installation: ignore or not?

Many property owners are tempted to save money and connect the electrical system of a new living space to the existing electrical service panel in the main house, and this decision can have several unpleasant consequences. Firstly, one electrical meter box cannot cope with the load of providing light to two large spaces at once, which means that the risk of an emergency situation and, as a result, a fire increases. Secondly, during a routine inspection, specialists can detect this violation, which will first result in a warning and, in case of repeated violation, a fine. Based on all this, from the point of view of safety and financial stability, the best solution is to install separate meters in ADUs rather than ignoring this decision.

ADU Electrical Wiring & Basic Concepts

If by this point you still feel constrained due to a lack of special knowledge on the topic of electricity, then now we will quickly fix it.

Deciphering these five concepts will instantly make you a person immersed in the topic of electrical maintenance:

• Main service panel is the “boss” in the world of power supply of your living space. You can find the main panel in the primary living structure, and it shows all the key parameters of the state of the electricity supply system.
• Sub panel – by the name, we can easily guess that this panel is an addition to the existing electrical service panel. In most cases, the sub-panel is responsible for the power supply of your ADU project.
• Electrical service size is the first non-physical object in our list of terms, which is the amount of amperage that enters the electric service panel. It is noteworthy that in the digital equivalent, the amperage has only integers, for example, 100A or 400A.
• Service conduit: we said that “the amount of amperage that enters the electric service panel”, however, through which object does this current move? That’s right, through service conduit, which is the link of the entire chain from the main substation to the panel in your building.
• The main breaker is the “red button” in the existing service panel, which allows you to completely turn off the electricity throughout the house. This is necessary in the context of safety, for example, when there is a risk of flooding, or it is raining outside with lightning. In addition to the main breaker, you can find many other breakers on the panel, each of which is responsible for a specific room in your house or for home appliances, e.g., an electric stove.

Now you are in the course of basic concepts, and this knowledge will definitely be helpful to you in the long run perspective, when you have to do electrical work on your own or discuss upgrading with specialists, or maybe you use them during a quiz with friends.

ADU Electrical Panel Upgrades

Your property is a large ecosystem that requires changes from time to time. It can be something insignificant, for example, the purchase of new equipment for a children’s room, or something global, e.g., the panel’s replacement.

Below, we have collected for you the most common situations when homeowners have an urgent need for the ADU electrical panel upgrading:

1. Deterioration of the electrical panel. When it comes to upgrading an electrical panel, the most frequent reason is its wear and tear. Often, replacement in this case is necessary for homes older than 20–25 years, however, if you use electricity very actively, e.g., turn on led lighting every evening or use an electric dryer every day, then we can reduce this number to 15 years.
2. Changes in local regulations. Local authorities in any city are constantly making changes to construction regulations, and they affect the power supply system too. Examples of such changes may be the requirement of installation of an underground conduit with a different diameter or a change in the angle of the conduit. In such situations, specialists modernize not only the internal power supply lines, but also the electrical panel itself.
3. Increase the power. You’ve probably come across a situation where you turn on a lot of household appliances at the same time and your electrical panel stops working. This is due to the inability of the meter box to accept the current power, and this is direct evidence of the need to replace it. If you want to use all the new household equipment, then your electrical panel needs upgrading to generate enough power.
4. Suspicions about the safety quality. Homeowners use their electrical panels every day; many of them also often note that sparks fly during the process of switching breakers from the meter, while the overwhelming percentage of property owners simply ignore this fact. This is unacceptable because even one spark is a threat to the safety of your home and its residents. If there are sparks, a specialist will tell you to think about upgrading the electrical panel.
5. Increase energy efficiency. We live in a world where everyone has to take care of the environment, and you can start this process by installing an energy efficient electrical panel in your accessory dwelling unit. In addition to following the concept of careful handling of power, if you use electricity efficiently, this will lead to lower utility costs.

Finally, if you notice any mechanical damage in your meter box, for example, melted circuits, cracked frame, or blackened wires, then in no case hesitate to upgrade the electrical panel in your ADU.

Underground vs. Overhead ADU Power Lines

The building process includes many aspects that you need to analyze in advance and that are almost impossible to change after the project completion. One of these factors is the laying of power lines, and homeowners have three options in this matter.

Let’s list each of them:

• Underground lines. Despite the reliability of underground lines in terms of their protection from external stimuli, this option has one substantial disadvantage. This point lies in the fact that lines already pass under the same property, which means that even at the design stage of the ADU building, it is necessary to consider whether they will intersect or interfere with each other.
• Overhead lines. In the case of this option, the builders can also warn you about the possibility of interference. However, unlike underground lines, you can transfer to overhead lines. Of course, this will lead to additional costs, which usually do not exceed the threshold of $4000-$5000, however, as a result you will get an installed electric panel with a completely independent network of lines.
• High voltage power lines. Each of us has seen electric poles that stand on the roads on every street. In agreement with local utilities, these high-voltage power lines can service your transformer in the ADU. However, many hidden legal aspects exist here; for example, the ADU cannot stand too close to these lines.

On the whole, each of these options has many legal and bureaucratic nuances that only a specialist can figure out. Therefore, before connecting your service panel to one of the lines, be sure to consult with the masters.

Professional ADU Electrician: Reasons for Hiring

During the construction or renovation of ADU projects, homeowners tend to do some work themselves rather than trusting professionals to do it. This decision is reasonable in the case of wallpapering or plastering surfaces, but it is unacceptable when the property owner is trying to install a new service panel.

In the matter of electrical work, you cannot do without the help of a professional electrician, and there are three reasons for this. Firstly, experts know not only common issues, but also all the smallest nuances of working with electricity. This allows them to do their work efficiently and not harm themselves, unlike homeowners who electrocute themselves while working and end up in the hospital with burns.

Secondly, the knowledge of the craftsmen allows them to select the right panels that will meet all your needs, fit the parameters of the ADU building and comply with all legal norms. Thirdly, the work of the master is a guarantee of durability, such an installed panel will not burn out after two weeks of active use.

Frequently Asked Questions — FAQ

In which cases does the homeowner need to install separate metering for the ADU project?

The answer to this question lies in the location of your ADU. According to the regulations, if the unit stands at a distance of more than 150 ft.., then you need to install a separate panel, if not, then you can install it in the main house to simplify access. You should observe these conditions both from the point of view of safety and in the case of a scheduled inspection.

How many amps do I need to provide for a standard accessory dwelling unit?

The average ADU’s electricity consumption ranges from 80 to 100 amps. However, homeowners often equip the living space with various appliances, so any electrician will advise you to install the meter at 125 amps of power so that the installed panel does not always work at the high limit.

What is the average cost of installing new panels for ADU?

The average costs for an electric panel installation service rarely exceed $10000-$12000, however, very often there is a need for additional costs. The explanation for this lies in outdated underground transmission lines or unsafe existing wiring, which a homeowner also can replace so that the panel will work efficiently and safely in the future.

What are load calculations in the context of the ADU power supply system?

This is a mathematical operation that allows you to estimate how much electrical energy a living space needs to function fully and meet basic household needs. Only specialists can make such calculations correctly because they take into account all aspects of the system.

What are the advantages of hiring a licensed electrician for the electrical panel installation in the ADU project?

Electrical work is the prerogative of exclusively qualified electricians. Specialists know how to safely handle electricity, how to ensure safety on the entire property, including the ADU, as well as how to set up the operation of the electric panel so that it does not require expensive upgrading after two months of operation.