Avoiding AFCI Breaker Wiring Pitfalls in Commercial Solar Projects

Commercial photovoltaic power plants have a large scale and high DC voltage. Whether the AFCI Breaker (arc fault circuit breaker) is correct is directly related to whether it can prevent electric arc fires. Many projects have purchased good equipment, but due to poor wiring, they often trip incorrectly or fail to respond when faults occur, leaving hidden dangers and wasting money. Today we will talk about the key points to avoid pitfalls in commercial photovoltaic AFCI Breakers, and by the way, why Fengzhi’s AFCI is particularly worry free in terms of wiring.

Pit 1: Failure to follow the “string current”/voltage “wiring specifications” results in overload when used

The series current of commercial power stations is generally greater than that of household power stations (for example, 20A or more). If a thin wire is randomly connected, AFCI Breaker will heat up when the current is high, causing tripping and severe wire burning. Many construction teams want to save time and use the same things as household appliances. The 10 square meter line had problems as soon as it was connected to the grid.

Key points for avoiding pitfalls: First check the rated voltage of the AFCI Breaker (such as Fengzhi’s rated voltage), AFCI has models such as 20A and 32A, and then select the wire specification according to “current” × 1.2- for example, select the wire specification - for example, for a 20A AFCI, use at least 16 square meters of DC cable; 32A requires 25 square meters. Fengzhi’s product manual will clearly specify the marking specifications and provide a selection table, so you don’t have to calculate blindly to avoid stepping on lightning.

Pit 2: Positive and negative reversal, equipment is directly scrapped

The DC side has positive and negative terminals, and the wiring terminals of the AFCI Breaker are also divided into positive and negative. If the connections are reversed, internal components may burn when powered on. I have seen a project before. The construction team reversed the positive and negative signs. As a result, all three AFCI machines were broken, which not only delayed the construction period, but also cost tens of thousands of yuan to replace them.

Key points for avoiding pitfalls: Before wiring, check the “-” symbol on the AFCI “Breaker” (which is very obvious), and then correspond to the positive and negative connections of the string. The positive and negative connections of Fengzhi. AFCI also has a “reverse connection design”, where positive and negative connections cannot be inserted. Even if forced to connect, the internal protection circuit will trigger and will not directly burn the equipment, acting as a layer of insurance.

Pit 3: The wiring terminals are not tightened, resulting in electrical arcing during use,

The series current of commercial power stations is very high. If the terminals are not tightened, the circuit resistance will increase, and it is easy to heat up and feel cold when powered on - this actually makes the wiring terminals not tightened, and the circuit resistance will increase. AFCI Breaker frequently alarms and even causes its own malfunctions. Some projects have just been installed and trip after six months. When they are opened, the terminals will loosen.

Avoiding pitfalls: Use a torque wrench to press. Key points: Use the torque wrench AFCI Breaker to twist the terminal (as required by Fengzhi) to 8-10N · m, and do not tighten your hand to the “feel tight” position. Fengzhi’s terminals have also been designed with anti slip features, which make them less likely to loosen after tightening. Even with long-term vibrations (such as roof wind), they can maintain good contact and reduce future failures.

Pit 4: There is no “repair space”, and it will take half a day for later maintenance and dismantling

There are many devices in the commercial power station combiner box, and some construction teams install multiple devices. Some construction teams fill the wiring so tightly that they cannot even reach their hands next to the terminals in order to install multiple AFCI devices. Afterwards, if the equipment needs to be replaced, the surrounding wiring must be removed first, which takes half a day to complete and delays power generation.

Key points for avoiding pitfalls: Leave space according to the installation dimensions of the AFCI Breaker. For example, the AFCI of Fengzhi has a total width of 45mm, leaving at least a 10mm gap between the two units and a 10mm gap in front of the terminals. The operating space should exceed 200mm. Fengzhi also provides a “combiner box integration solution” to help you plan equipment layout in advance, without calculating your own space, with neat installation and easy maintenance.

Pit 5: If there is no communication line connected, the fault cannot be found

If the communication cable of the Breaker is not connected, AFCI can only determine the fault by observing the display lights on site. There are so many commercial power stations that it is impossible to quickly locate them. There was a project before that was not connected to communication. After AFCI tripped, the master climbed up for 3 days and found a faulty string on the roof, resulting in thousands of kilowatt hours of electricity loss.

Key points for avoiding pitfalls: Be sure to connect the RS485 communication line (Fengzhi AFCI comes with a communication interface), connect it to the combiner box gateway, and then connect it to the monitoring platform (such as Fengzhi’s communication interface) SafeSolar platform. So, no matter which one it is. If there is a problem with AFCI, the phone can see the specific location and fault type, without the need for blind on-site search, which improves operation and maintenance efficiency by 10 times.

Why choose Fengzhi AFCI Breaker? Easy wiring and pit prevention

Fengzhi’s AFCI not only has reliable performance, but also has many details in “preventing wiring lightning strikes”:

Comes with a “wiring guide label”, with clear identification of positive and negative, communication, and power lines, ensuring that beginners will not make mistakes in wiring;

The terminals are made of tin plated copper material, which has good conductivity and is not easy to oxidize. The wiring does not need to be loose and loose over time;

Support “hot swappable wiring” (under power-off conditions), no need to disassemble the entire combiner box when replacing equipment later, 10 can be completed in a few minutes;

If you are unsure, Fengzhi can also send technicians to provide on-site guidance on wiring to ensure smooth installation and use.

Summary: When installing AFCI in commercial photovoltaics, do not be careless with wiring

AFCI Breaker is the key to fire prevention in commercial photovoltaics. Remember the five points of “matching specifications, distinguishing positive and negative, tightening terminals, leaving enough space, and connecting communication”, and then choose Fengzhi AFCI to truly play its role, which can not only prevent fire but also maintain the power station. Only when the power station is firmly grounded and generates electricity can it be worry free.