Singapore Solar Installation Standards

Every component in a Sunollo residential solar installation is specified to meet or exceed Singapore's technical standards. This page documents the grade, rating and compliance requirement for each balance-of-system (BOS) element — cables, structure, protection devices, earthing, conduit, metering and labelling — under SS 638:2012+A1:2018, CP 5:2022 and EMA regulations.

These standards apply to all Sunollo installations in Singapore. Site-specific conditions (coastal exposure, roof load, cable run length) may impose higher requirements — final specifications are confirmed by a Sunollo Licensed Electrical Worker (LEW) during the site assessment.

Cables — DC (Panel to Inverter)

Attribute	Requirement	Standard / Reference
Cable type	Double-insulated single-core solar cable, tinned copper conductor	IEC 62930 / EN 50618
Voltage rating	1000 V DC (1500 V DC for systems >1000 V DC)	SS 638 §6.1
Minimum conductor size	4 mm² for string runs; 6 mm² where string length >15 m	SS 638 §6.2
Insulation	XLPE, halogen-free, UV-stabilised; rated to 90 °C continuous / 120 °C short-circuit	IEC 62930
Outdoor service life	≥ 25 years under Singapore tropical conditions	SS 638 §6.1
Conduit protection	Required for all exposed roof runs; UV-grey PVC or galvanised steel conduit	SS 638 §6.3, CP 5:2022
Connector standard	MC4 or compatible IP67 rated connectors (IEC 62852)	IEC 62852

Cables — AC (Inverter to Distribution Board)

Attribute	Requirement	Standard / Reference
Cable type	PVC or XLPE insulated, copper conductor, multi-core	SS 217, CP 5:2022
Voltage rating	450/750 V minimum (single-phase residential); 0.6/1 kV recommended	CP 5:2022 §6
Minimum conductor size	10 mm² copper for most residential inverters (3–10 kW); sized per current rating tables	CP 5:2022 Table B1
Derating	Cable ampacity derated for Singapore ambient (40 °C ambient baseline per CP 5)	CP 5:2022 §7
Protection	PVC conduit mandatory where exposed to mechanical damage or UV; IP44 minimum fittings	CP 5:2022 §9
Colour coding	Phase: Brown / Black / Grey; Neutral: Blue; Earth: Green-Yellow per SS 638 and CP 5	SS 638 §12

Steel — Mounting Structure

Attribute	Requirement	Standard / Reference
Purlin / rafter anchor brackets	Hot-dip galvanised mild steel, minimum zinc coating 85 μm; or 316L stainless steel for coastal exposures (within 1 km of coast)	SS ISO 1461, SS 638 §5
Inland bracket grade	304 stainless steel acceptable where not exposed to marine atmosphere	ISO 3506
Minimum bracket thickness	2 mm for intermediate clips; 3 mm for primary purlin anchors	SS 638 §5.2
Fasteners (bolts, nuts, washers)	Grade 316 stainless steel, M8 minimum for structural connections	ISO 3506
Wind load design basis	Basic wind speed 28 m/s, Terrain Category 2 (suburban Singapore)	SS CP 3 Ch V Pt 2

Aluminium — Rails, Hollow Bars and Standoffs

The standard Singapore landed-home tile roof mounting system uses a 4-layer stack: (1) stainless steel L-bracket anchored to rafter/purlin → (2) aluminium hollow square bar (40×40 mm SHS) as standoff → (3) aluminium rail (C or T profile, 40 mm) → (4) aluminium mid- and end-clamps. Each layer carries its own grade requirement below.

Component	Alloy & Temper	Profile / Dimension	Surface Treatment	Standard
Mounting rail (on top of hollow bar)	6063-T5 or 6061-T6	C-profile or T-profile, typically 40 mm height	Anodised min. 15 μm (AA15) or powder coat min. 60 μm UV-stable	SS EN 755, SS 638 §5
Hollow square bar (standoff)	6063-T5 minimum	40×40×2 mm SHS or equivalent	Anodised min. 10 μm (AA10)	SS EN 755
Mid-clamps	6061-T6	Sized to panel frame (35–50 mm clamp range typical)	Anodised min. 10 μm	SS 638 §5.3
End-clamps	6061-T6	Panel-specific; captive spring models preferred	Anodised min. 10 μm	SS 638 §5.3
Clamp fasteners	M6 or M8, 316 SS	T-bolt + hex nut, locking washer	—	ISO 3506
Max unsupported rail span	≤ 1 400 mm (residential); confirmed by structural engineer for spans > 1 200 mm			SS 638 §5.2

Protection Devices — DC Side

Device	Requirement	Standard
String fuses	15–20 A rated for string current; gPV type; installed in IP65 combiner or at inverter DC input	IEC 60269-6 / UL 2579
DC isolator	Rated for full DC voltage + 25% margin; double-pole; mounted adjacent to inverter	SS 638 §7
DC SPD (Surge Protective Device)	Type 2 (Class II), 1000 V DC minimum, ≥ 40 kA discharge capability; installed at inverter DC terminals	IEC 61643-11, SS 638 §7.4
Arc Fault Detection (AFDD)	Recommended for Singapore installations; mandatory where insurers or BCA requires it	IEC 63026

Protection Devices — AC Side

Device	Requirement	Standard
AC isolator / disconnect	IEE-approved, double-pole; rated at minimum 125% of inverter rated output current	CP 5:2022 §13
AC MCB at DB	Dedicated solar circuit breaker; labelled "Solar Generation" per SP Group requirements	SS 638 §12, SP Group
AC SPD	Type 2 or Type 3 (Class II/III), 230 V; at the inverter AC output or main DB	IEC 61643-11
RCD / RCCB	30 mA rated; required if inverter does not have built-in isolation monitoring	CP 5:2022 §15

Earthing and Bonding

Element	Requirement	Standard
Equipotential bonding conductor	Bare copper or green-yellow insulated; minimum 6 mm² connecting all metallic mounting components (rails, frames, inverter chassis) to main earth terminal	SS 638 §8, CP 5:2022 §14
Earth electrode	Must connect to the building's existing earth electrode system; additional rod required if earth resistance >10 Ω	CP 5:2022 §14.3
Rail-to-panel bonding	Anodised aluminium provides adequate bonding where anodising is scraped at clamp contact; bonding continuity test required at commissioning	SS 638 §8.2

Conduit and Cable Management

Location	Conduit Type	IP Rating	Standard
DC cable on roof (exposed)	UV-grey PVC rigid conduit, or galvanised steel conduit for impact-prone areas	IP44 minimum	SS 638 §6.3
DC cable within ceiling cavity	PVC conduit or cable tray; separate from AC circuits	IP20 minimum (enclosed space)	CP 5:2022
AC cable on exterior wall	White rectangular PVC trunking (Sunollo standard) or round conduit; run level/plumb, corners mitered	IP44	CP 5:2022 §9
Penetrations (wall / fascia)	Sealed with fire-rated silicone or intumescent putty where passing through fire-compartment walls	—	FSSD requirements

Metering and Grid Connection

Element	Requirement	Standard / Body
Bi-directional energy meter	SP Group-approved digital meter with import and export registers; required for Enhanced Central Intermediary Scheme (ECIS) solar crediting	EMA / SP Group
Meter installation	Installed by SP Group licensed contractor in SP-approved meter box; Sunollo coordinates application	EMA Connections Code
Anti-islanding protection	Inverter must have certified anti-islanding function; tested to disconnect within 2 seconds on grid loss	SS 638 §9, EMA Technical Requirements
Power quality	Inverter output THD < 5%; power factor > 0.85 per EMA grid code	EMA Grid Code

Labelling and Documentation

Location	Required Label	Standard
Inverter (DC side)	"SOLAR ARRAY — DANGER: DO NOT OPEN — 600 V DC" (or actual voltage); rated current and voltage	SS 638 §12
Inverter (AC side)	"SOLAR INVERTER — ISOLATE BEFORE SERVICING"; max output current	SS 638 §12
Main distribution board	Dedicated solar MCB labelled "Solar Generation"; warning label indicating live when grid off	SS 638 §12, SP Group
DC isolator	"DC ISOLATOR — SOLAR" with on/off indication	SS 638 §12
All junction boxes	Circuit identification; voltage / current rating	SS 638 §12
As-built drawings	Single-line diagram, cable schedule, and site layout plan submitted to EMA via SP Group portal	EMA Connections Code

How Sunollo ensures compliance: Every installation is designed and supervised by a Singapore Licensed Electrical Worker (LEW). All materials are procured from approved suppliers carrying the relevant certifications. An independent commissioning test is performed before grid connection, and as-built documentation is submitted to EMA on the homeowner's behalf.