Third Party Inspection of Control Panel
An electrical panel is nothing but a load control center. All the electrical actions such as power distribution, power transmission, and power system protection are performed by using the electrical panels only. The electrical scheme/wiring diagram will be established using electrical panel & Electrical panels are the practical installation of the electrical wiring diagram. It consists of the trip circuit, closing circuits, bus bars, cables, MCCB’s, MCB’s, MPCB’s, NO & NC’s, etc. Electrical panels are ensuring the safe power distribution to the load. Electrical panels are manufactured by rolled steel and well-shaped either rectangle or square.
Control Panel are classified different types as per application.
Control Panel: Control Panel consists of circuit control elements such as protecting relays, meters, alarm circuits, PLC’s, SMPS, Small power source, etc. These panels will be placed near the maintenance operator’s place or the operator will be monitored by the control panel.
PCC panel: PCC is a short form of Power Control Center. This is the heart of the control circuit. The output of the generators or transformers is given to PCC. The major power circuit equipment will be installed in this panel. It consists of circuit breakers, Busbar, PT’s (Potential Transformer), CT’s (Current Transformer), insulators etc. Major protection circuits will be installed in this panel to protect transformers, Motors, Generators etc. The output Power from the PCC panel will be distributed to MCC panels via feeders.
MCC Panel: MCC is a short form of Motor control center. It consists of Feeders. And feeder contains a motor starter, SFU, MCB, MCCB, MPCBs, Control transformer, meters etc. Once you open the door of the MCC panel doors you can access all the circuit breakers or fuses. Usually one of these panels feeds all the circuits in the power plant or other electrical applications but there may be a situation where there is another “sub-panel” such as a welding distribution board or lighting distribution board serving a dedicated area.
MLDB- Main Lighting Distribution Board: Distributes power to the lighting circuits.
The common reasons for Electrical Control Panel Failure:
Tripped breakers or blown fuses: Depending on how an electrical circuit is protected, an overload will cause a breaker trip or a blown fuse. If your electrical system is acting funky, check for tripped breakers or blown fuses first. These circuits are isolated so the control system could appear to be functioning normally but part of the systems process won’t function.
Power Spikes and Surges: Unexpected electrical events from the power company or the elements can damage panels, leading to lost controller programs, faulted VFDs, and damaged electronics. Sadly, much of the damage can be instantaneous.
Cut or ground wires in the conduit systems: Electrical contractors will often use Electrical Metallic Tubing (EMT) conduit or flexible conduit in places where they are stepped on or damaged by contact. When damaged, the conduit can separate from the wires and cut into them causing them to ground on the conduit or cut in half. This can cause tripped breakers, blown fuses, shorted power supplies, and unexpected machine operation that could seriously injure personnel. To prevent this, perform routine inspections of conduit systems.
Tripped overloads on power circuits: Most motor starters are protected using an overload set to the Full Load Current of the motor. If the electrical load on the motor is excessive or the motor windings short, the current will exceed the motors rated full load amps causing a trip. In most cases, the overload is wired using the neutral so when troubleshooting, measure from the neutral on the contactor and not the ground. Additionally, most overloads have an indicator on the front that alerts you when it’s tripped. Correct the problem and then use the overloads reset button to reset the device.
Loose or disconnected wires: Many manufacturers use screw terminals to fasten their electrical wires. These types of terminals are susceptible to the vibration that can cause loosening over time, eventually leading to an open circuit that is difficult to troubleshoot due to the appearance of a connected terminal. Regularly inspecting your screw terminals for tight connections will prevent this. Alternatively, many companies, including Innovative IDM, offer spring clamp terminal technology that won’t loosen and rarely has to be checked.
Carbon build-up on relay or contactor contacts: Carbon naturally accumulates on contacts that arc when opening and closing. Over time, carbon will cover the contact, blocking conductance through the contactor or relay. An easy way to check is to energize the relay and use a voltmeter to measure across the contacts to verify the contacts are conducting. If the voltage is read across the contacts, you’re OK. If not, there’s your problem: Use contact cleaner to remove the carbon or replace the component if beyond cleaning.
Manufacturing Defects of Electrical Control Panel:
Control Panel specifications are key to matching load and operating conditions with electrical protection and efficiency. Nameplate provides important information relevant to its selection and application. Front panels and faceplates may include metal or plastic substrates, depending on the application specifications, and can be mounted with studs, adhesives, or fasteners. Digital or screen-printed graphics provide visual guidance for operators and incorporate the labeling of operator devices to ensure usability. Therefore, faceplates must have the durability necessary to remain readable for the life of the asset.
All control panel inspection and testing are done against the approved drawings, purchase order specifications, purchasers or company standards, and within the practices and rules of the country, state or province, and any government decrees, laws, ordinance, or regulation as may apply.
The applicable codes and specifications for a control panel that is under the construction process is:
Applicable IS Standards for Control Panel
The applicable codes and standards may be based on any international standards.
This content is general and can be useful for all recognized standards. Ref. some of IS Standards as:
Third Party Inspection Document Review for Control Panel
When Third Party Inspection agency perform the Inspection of Control Panel, The followings documents are to be checked / verified (But Not Limited)
These are the list of documents that are normally agreed upon to be presented to the inspector:
A very important aspect is the technical documentation that has to be prepared by the manufacturer of the Control panel that must include the following characteristics:
Third Party Inspection of Control Panel
During the Third-Party Inspection of Control Panel, the Third-Party Inspection services provider Third Party Inspection Agency – inspector take into the considerations of the Followings
The review includes checks on:
Ancillary items may be supported by test certification, or by certificates of conformity. It is necessary the content of certification to be appropriate to the required scope of the items.
It is also necessary to check material identification with the control panel drawing datasheet, material list and other specifications as appropriate.
When the third party inspector carries out the material inspection, then provides the inspection visit report, the report contains the following items:
Construction of Control Panel:
Insulation Resistance Test
Insulation resistance is measured between control circuits and earth (with sensitive devices excluded) with a 500V Megger. Similarly, insulation resistance is measured in all applicable permutations for any power circuits, if these are included within the control system, with a Megger selected to the voltage calculated appropriate to the applicable specification. The test result depends to the circuit but would not be acceptable if it is less than 2 Megohms.
Withstand Voltage Test / Dielectric Test
A power frequency voltage of 1.5 kV is applied between control circuits and earth for 1 minute. Similarly, power frequency voltage, calculated appropriate to the applicable specification, is applied to all applicable permutations for power circuits for 1 minute.
The test would be acceptable if the no flashover and puncture occurs during the test.
Control circuitry is functionally tested and circuits proven by appropriate tests. The test result would be acceptable if meet approved schematic diagrams (including appropriate, recorded, “as built” alterations) and project philosophy.
Mechanical Operation Test
The following mechanisms are checked for operation:
The test would be acceptable if all the mechanisms work correctly.
Painting & Coating Inspection
Surface preparation for painting is checked for the following points, according to specification by third party inspector:
It is necessary surface condition to be free from pin-holes, runs damage and other discontinuity.
Packing, Marking and Shipping
The following points are checked by the third party inspector for packing inspection:
Verify that the packing materials conform to specifications and accepted practice for the mode of transport
Third Party Inspection Agency in India
We are a leading Third-Party inspection Agency in India providing Third Party Inspection services in most of industrial sectors – Mechanical, Electrical, Engineering, Handicraft, Food Products, FBO, Construction, Infrastructure, Pre-shipment inspects etc many more Industrial sectors.
We have Highly Experience Team of Engineers team with us – who have vast Experience in Inspection of Electrical products including – Control Panel.
The Control Panel has wide application in Industrial and Domestic Applications. So, importance of its Quality and Reliability must be checked by Manufactures before delivery the product or get it be Inspected by Third Party Inspection Agency to ensure the same.