{"id":3363,"date":"2026-09-30T01:00:00","date_gmt":"2026-09-30T01:00:00","guid":{"rendered":"https:\/\/cnsuton.com\/?p=3363"},"modified":"2026-10-06T06:38:19","modified_gmt":"2026-10-06T06:38:19","slug":"afdd-selection-single-phase-circuits","status":"publish","type":"post","link":"https:\/\/cnsuton.com\/pt\/blog\/afdd-selection-single-phase-circuits\/","title":{"rendered":"Como selecionar um AFDD para circuitos finais monof\u00e1sicos"},"content":{"rendered":"

AFDD selection<\/strong> for a single-phase final circuit starts with the fire-risk decision and the exact circuit to be protected. Confirm the adopted installation rules, connected loads, conductor and neutral arrangement, prospective fault current, required overcurrent and residual-current protection, and the AFDD manufacturer\u2019s permitted configuration. Then select the exact product code and record its wiring, test and maintenance instructions. An AFDD is a circuit-specific protective device; a familiar front shape or current rating alone cannot prove that it suits the installation.<\/p>\n

\"SUTON
Article-specific cover based on the real ETB9LAF-40 product photo.<\/figcaption><\/figure>\n

Begin with the final circuit and fire-risk decision<\/h2>\n

An AFDD is selected for a specific final circuit, not as a general promise that every downstream arc will be found. Identify the rooms and loads served, the cable route, the presence of combustible materials, the likely consequences of a wiring fault, and the adopted installation rules. Record whether the project requires an AFDD, recommends one after a risk assessment, or has a client specification. Those are different starting points. A decision made for a bedroom circuit should not simply be copied to a workshop circuit with a different load and wiring environment.<\/p>\n

Draw the single-line circuit from the source to the final outlets or fixed equipment. Note the line and neutral path, protective-earth conductor, earthing system, source switching, distribution board, conductor cross-section and installation method. Identify whether the proposed AFDD protects one final circuit and whether any branches, multiwire arrangements or shared neutrals change that boundary. If a circuit diagram is incomplete, complete it before choosing a catalogue number.<\/p>\n

Separate arc detection from the other required functions<\/h2>\n

An AFDD analyzes electrical signatures associated with hazardous arcing. It does not remove the need to check overload, short-circuit, residual-current and isolation protection. The proposed product may integrate an overcurrent device, integrate an RCBO, or be a separate unit used with a declared protective device. The IEC 62606 AFDD scope<\/a> describes these broad configurations; it is not a certificate for a specific SUTON model or installation.<\/p>\n

On the schedule, identify which device provides each function. If the arc device is paired with an MCB, confirm how residual-current protection is supplied when the adopted rules require it. If an AFDD and RCBO are integrated, verify the rated current, trip curve, residual-current type, sensitivity and short-circuit capacity as well as arc detection. The AFDD versus RCBO guide<\/a> explains the functions, and the combination guide<\/a> discusses arrangement choices.<\/p>\n

\n\n\n\n\n\n\n\n\n\n
Selection input<\/th>\nQuestion to resolve<\/th>\nEvidence to retain<\/th>\n<\/tr>\n<\/thead>\n
Final-circuit purpose<\/td>\nWhich fire-risk or project rule is the AFDD addressing?<\/td>\nRisk assessment and circuit schedule<\/td>\n<\/tr>\n
Arc-device arrangement<\/td>\nIs the AFDD standalone, combined with MCB\/RCBO, or paired?<\/td>\nExact model and declared combination<\/td>\n<\/tr>\n
Overcurrent duty<\/td>\nDoes current rating and short-circuit capacity suit the cable and supply?<\/td>\nLoad calculation and fault study<\/td>\n<\/tr>\n
Neutral and poles<\/td>\nWhich conductors are sensed and opened?<\/td>\nManufacturer terminal diagram<\/td>\n<\/tr>\n
Connected loads<\/td>\nCould electronic controls or switching produce operating signatures needing review?<\/td>\nLoad list, manufacturer notes and test plan<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

This is a qualitative decision table. Use the exact manufacturer instructions and the project edition of the installation rules for ratings and limits.<\/small><\/p>\n

Match the product to the circuit, not the catalogue photograph<\/h2>\n

Confirm the AFDD’s rated voltage and frequency, rated current, poles, width, terminal capacity, line\/load orientation, arc function, any integrated overcurrent or residual-current function, accessories and permitted busbar. Check ambient and enclosure conditions. A dimension or front photograph cannot prove reverse-feed capability or the behavior of an electronic sensing circuit. Ask the supplier for the exact model code and the installation sheet that belongs to it.<\/p>\n

The SUTON ETB9LAF-40 product page<\/a> is one physical reference for a single-phase device. The ETB9LAF-63 product page<\/a> shows another SUTON AFDD family. They are not interchangeable just because both have an orange test button. Compare terminal diagrams, pole functions and declared protective combinations. The product image below is a real reference; model-specific electrical claims must come from the offered datasheet.<\/p>\n

Check normal loads and avoid false assumptions<\/h2>\n

List LED drivers, power supplies, variable-speed appliances, switched motors and other loads that can make the current waveform less simple than a resistive circuit. The purpose of the load review is not to declare those loads incompatible. It is to tell the supplier and designer what the device will actually see during start, steady operation and shutdown. If a load or control system changes after installation, repeat the compatibility review rather than treating the original selection as timeless.<\/p>\n

For a multi-source or backup installation, draw every operating mode. Confirm where the supply enters the AFDD, whether a source can backfeed its load side, and what the manufacturer permits. The IET discussion of bidirectional protective devices<\/a> illustrates why line\/load direction can matter for electronic protective devices. Apply it as a design prompt, not a substitute for SUTON documentation.<\/p>\n

Coordinate with other devices and board layout<\/h2>\n

Check the prospective short-circuit current at the installation point, upstream protective device, conductor size and enclosure rating. If a claimed backup or selectivity combination is needed, request a manufacturer table for the exact device pair. Confirm physical fit in the distribution board, safe terminal access, compatible busbar, neutral routing, labels and space for accessories. The arc detector’s presence does not improve a cable termination that has been left loose or an enclosure with inadequate clearance.<\/p>\n

The IET’s AFDD guidance<\/a> explains the fire-protection objective and notes the practical importance of board space and busbar arrangement. Its discussion is tied to its regulatory context. For another market, use the locally adopted rules and the actual project specification. Do not put a universal \u201cmandatory\u201d label on an AFDD selection without identifying the jurisdiction and circuit type.<\/p>\n

Make the RFQ answerable<\/h2>\n

Send the supplier the system voltage, frequency, source modes, single-line diagram, final-circuit load list, conductor schedule, estimated maximum and minimum fault current, overcurrent curve and rating, residual-current requirement if any, neutral arrangement, board layout, busbar type, ambient range and accessories. Ask for a completed compliance schedule with the exact model and document revision beside every requirement. A blank response should remain unresolved; it is not evidence of compliance.<\/p>\n

Request the AFDD detection scope, built-in self-test description, test-button procedure, trip indication and post-trip diagnostic method. If the supplier offers an alternative model, compare its terminal map, protection functions, size and commissioning method with the base offer. Keep the accepted variation with the purchase order. The series-versus-parallel arc guide<\/a> gives context for the arc paths that the design review must consider.<\/p>\n

At goods receipt, compare the delivered model, pole arrangement and marked ratings with the accepted compliance schedule. Record any substitution before installation; a familiar series name or similar enclosure does not confirm that the ordered protection functions were supplied.<\/p>\n

Commission without creating a hazardous arc<\/h2>\n

Before energization, confirm model identity, terminal position, conductor placement, protective-earth continuity, torque, barriers and labels under the approved safe-work procedure. Use the manufacturer test control and record the indicated result. Do not create a live arc with loose wires or tools to \u201cprove\u201d the AFDD. That experiment is unsafe and may not represent the product-standard test. Check any integrated overcurrent or residual-current function by its separate approved procedure.<\/p>\n

Record the as-left single-line diagram, catalogue code, settings, test date, operating mode, instrument where applicable and the person responsible. Give maintenance staff the fault-indication legend and reset procedure. A future nuisance trip should lead to diagnosis of the circuit and load, not automatic removal of the AFDD. HSE electrical-safety guidance<\/a> reinforces competent work and safe isolation.<\/p>\n

What to keep in the project file<\/h2>\n

Keep the risk decision, approved circuit schedule, load list, fault study, supplier compliance answers, model-specific instructions, board drawing, test record and handover limitations together. State which source modes and loads were covered. If the board is expanded, the client changes a load, or a different AFDD is substituted, repeat the affected checks. The circuit-breaker types guide<\/a> provides the wider protection context.<\/p>\n

Before releasing the purchase order, ask a second reviewer to trace the selected AFDD from the final-circuit schedule through the single-line diagram, product code and board layout. This short cross-check catches an especially expensive mistake: a valid device selected for the wrong circuit or source mode. Record any open condition beside the affected line item and close it before shipment.<\/p>\n

Keep the approved reviewer, date and document revision on the same record so procurement and commissioning teams can identify the actual basis for the decision.<\/p>\n

\"Original
Original SUTON product photo; verify the offered code and pole function.<\/figcaption><\/figure>\n
\"Original
A second SUTON AFDD family provides a visual comparison, not proof of interchangeability.<\/figcaption><\/figure>\n

Educational video<\/h2>\n

This independent educational demonstration explains AFDD principles and testing concepts. It does not replace the SUTON manual or authorize live-fault experiments.<\/p>\n