What is service entrance equipment?

The service entrance is where the cables linked with the heaping side of the meter that enter the house or structure. A breaker or wire box is commonly thought of as the electrical entrance in a home. To supply capacity to the dwelling, administration entrance drops are used. The houses can be serviced from the power shaft of the service organisation either overhead or underneath.

The Service Entrance is where power enters the drop. The service equipment have electric meter, which measures the amount of electricity provided to the home, and the service panel, which houses the circuit breakers or fuses, they are both located at the service entry. The service panel also distributes power to the house's numerous circuits.

Following are the Service entrance equipment's.

Service Drop

An overhead electricity connection that runs from utility lines to the service entrance is called as Service Drop.

The figure shows a schematic arrangement of service drop with two 120 V wires and a neutral conductor. The three lines might be separate conductors or part of a triplex cable with three conductors as shown in the figure.

The three conductors that make up the service drop are two hotlines and one neutral. Each hotline has a 120 V potential to the neutral line. There is a potential 240 V differential between the two hotlines. This is why the service is designated as 120/240 V.

Mast and Clevis Service Drops

The Overhead service drops are classified into two types: mast and clevis. The figure shows schematic diagram of a mast service drop. The conduit and weather head that protrude upward from the roof are referred to as the Mast. At the mast knob, the service drop is joined to the mast.

The conduct tails (also known as drip loops) serve two functions. For starters, they give slack, which decreases mechanical loads on electrical lines. This is known as strain alleviation. Second, they prevent rainwater from flowing along the lines and into the service drop conduit.

As seen in above figure, a clevis service drop has fasteners that secure the electricity lines or triplex cable to the side of the house. The connectors that fasten the conductors to the building are referred to as Clevis. It is worth noting that the weather head and conduit are fixed to the side of the house below the roof line. The clevis service drop is distinguished from the mast service drop by this.

Service Lateral

The above figure shows an underground service connection, often known as a Service Lateral. The primary power lines connect to the pad transformer input via the conduit. The transformer output is connected to the electrical service metre through secondary power cables.

Transformers are electrical devices that are used to increase or decrease voltage levels. The transformer is employed in this scenario to reduce the voltage from the utility to the 120/240V residential level.

Service meter

The customer's energy use is measured via the service metre. There are two electrical service metres, one with an analogue display (rotary dials) and one with a digital display. Kilowatt-hours (kWh) are the units of energy used by the electrical service. A kilowatt-hour is the quantity of energy utilized in one hour, which may be calculated as:

${\mathrm{E}}_{\mathrm{kWh}}=\frac{\mathrm{P}\times \mathrm{t}}{1000}$

Here,

P= power in watts (W)

t= time in hours (h)

1000 in the denominator of the equation converts the power to kilowatts (kW).

Main Disconnect

In the event of an emergency, every residential service entrance must have a method of disconnecting the electrical power feed. The Main Disconnect switch (or breaker) is sometimes an Externally Operated (EXO) Switch located between the service metre and the electrical panel. In other circumstances, the electrical panel houses one or more circuit breakers that offer the required main disconnect capability.

The breaker(s) must be in series with both hotlines, regardless of the type of main disconnect employed. All circuits must be switched off from power (interrupt current) by the main disconnect. Only if it is connected in series with them will this be possible.

Service Panel

The service panel is the final component of the service entry. The service panel serves two key purposes:

1. It houses the components for overload prevention (circuit breakers in most cases, and fuses in older panels).
2. It acts as a link between the main Feeder and the Branch Circuits.

Grounding

Any domestic electrical system must have a continuous low-resistance ground path. This ground path ensures that the voltage levels in a residential wiring system are steady and that the overload protection features are working properly.

In above figure, a grounding circuit is shown. The neutral bus receives the incoming neutral line. The neutral bus, on the other hand, is connected to earth ground in one of two ways:

1. A ground conductor connects the neutral bar to the water or gas pipelines.
2. If neither of the connections in (1) work, a ground conductor is routed from the neutral bar to a Ground Rod located outside the home.

Figure shows a ground conductor that connects the neutral bar to a ground clamp on the water pipe. The grounding conductor makes a link between earth ground and the neutral bar in the service panel because the water pipes are underground. When a branch circuit's neutral wire terminates at the neutral bar, it becomes the circuit's ground conductor.

When water or gas lines can't provide the requisite ground connection, a conductor is connected between the neutral bar (at the service panel) and a grounding rod outside the house.

Advantages

• It is simple to increase the capacity of a service line.
• It is simple to locate and correct a fault.
• Erection is simple.
• It is economical.

Common Mistakes

• Load of wire - Load of fuse greater than wire load it may risky, so load of fuse should not be greater than wire load.
• Installation of wire in electric box - Wires should be installed carefully otherwise it may cause electric shock or short circuiting.
• Loose wire connection - Many houses have loose wire connections to electrical wires, which can lead to an electrical fire or electric shock.
• Length of wire in connection box - The length of the wire is the most critical factor in ensuring the safety of the electrical fitting.

Related Concepts

• Panelboard
• Switchboard
• Unit substation
• Meters

Context and Application

• Facilities on the property owner's side of the point of delivery required to accommodate public utility service.

In each of the expert exams for undergraduate and graduate publications, this topic is mainly used for

• Bachelor of Technology in Electrical Engineering
• Bachelor of Technology in Electronics Engineering
• Masters of Technology in Electrical Engineering

Practice Problems

Q1. An overhead electricity connection that runs from utility lines to the service entrance is called as ..................

A. Service Drop

B. Service Lateral

C. Service Meter

D. None

Answer: A

Explanation: An overhead electricity connection that runs from utility lines to the service entrance is called as Service Drop.

Q2. The conduit and weather head that protrude upward from the roof are referred to as the ...........

A. Service Lateral

B. Mast Service Drop

C. Clevis Service Drop

D. Service Meter

Answer: B

Explanation: The conduit and weather head that protrude upward from the roof are referred to as the Mast service drop.

Q3. A ............................ has fasteners that secure the electricity lines or triplex cable to the side of the house.

A. Service Lateral

B. Mast Service Drop

C. Clevis Service Drop

D. None

Answer: C

Explanation: A Clevis service drop has fasteners that secure the electricity lines or triplex cable to the side of the house.

Q4. ...................... are electrical devices that are used to increase or decrease voltage levels.

A. Service Lateral

B. Mast Service Drop

C. Clevis Service Drop

D. Transformer

Answer: D

Explanation: Transformers are electrical devices that are used to increase or decrease voltage levels.

Q5. The customer's energy use is measured via the ......................

A. Service Drop

B. Service Lateral

C. Service Meter

D. None

Answer: C

Explanation: The customer's energy use is measured via the service metre.