MIS 3002 issue 6, BS 7671 Amendment 4, G98/G99/G100, CT placement, string design for −10 °C and PAS 63100 battery siting.
Clamp the grid CT on a single conductor of the incoming meter tail, usually the line, between the meter and everything else, with the arrow…
Read the answer →02Every path between the grid and the house must be measured. With split tails, Economy 7 double tails or several meters feeding one installation,…
Read the answer →03Use matched DC connector pairs from the same product family and crimp them with the correct tools and procedure. MCS flags wrong tools as a major…
Read the answer →04G99 Issue 2 has three fast-track routes. SGI-1: units up to 32 A, limited to 16 A total, install then notify. SGI-2: aggregate under 32 A, export…
Read the answer →05G98 applies when all micro-generators and batteries at a connection point total no more than 16 A per phase: 3.68 kW single-phase or 11.04 kW…
Read the answer →06Work at Height Regulations 2005 apply. Plan the work, risk-assess it, use competent people and avoid, prevent or mitigate falls, usually with…
Read the answer →07In England, yes whenever the work adds a new circuit, replaces a consumer unit or alters circuits in a special location, which covers most PV and…
Read the answer →08For fixed PV and battery inverters, a dedicated radial circuit from the consumer unit with a suitable, bidirectional-rated protective device is…
Read the answer →09Under MIS 3002 the customer gets a document pack: commissioning forms and checklists, maintenance requirements, manufacturer manuals and…
Read the answer →10No later than 10 working days after commissioning, the MCS contractor registers the installation on the MCS Installation Database and generates…
Read the answer →11Adding an inverter or battery normally means a new circuit from the consumer unit, which needs an Electrical Installation Certificate and, in…
Read the answer →12Test and record each string using the BS EN 62446-1 PV array test report in MIS 3002 Appendix E: module type and quantity, design Voc and Isc,…
Read the answer →13Follow the IET PV Code of Practice decision tree in Section 5.13.2, Figure 5.7. MIS 3002 says correct use normally leads to protective or…
Read the answer →14Use an EREC G100 customer limitation scheme: the inverter or controller measures export at the connection point with a CT or meter and throttles…
Read the answer →15Customers apply directly to any SEG licensee, not necessarily their own supplier. Licensees normally ask for the MCS certificate or an equivalent…
Read the answer →16No UK rapid-shutdown requirement like the US NEC rule was found in MIS 3002 issue 6.0, MIS 3002:2025 or the DESNZ plug-in specification. MIS 3002…
Read the answer →17Provide a means to isolate the PV array DC from the inverter and an AC isolator for the inverter, lockable in the off position, rated for their…
Read the answer →18Fit dual-supply warning notices at the origin, meter, consumer unit and isolators, label the DC cables and junction boxes, and display the system…
Read the answer →19MIS 3002 Appendix F is advisory. For privately owned homes, customers do visual checks yearly, an MCS intermediate visit is suggested at 10 years…
Read the answer →20In England, permitted development usually covers roof panels projecting no more than 0.2 m and not above the ridge, flat-roof arrays up to 0.6 m…
Read the answer →21Only kits meeting DESNZ's Interim Product Specification v2 are legal: solar only, up to 800 VA and 3.5 A, a moulded BS 1363 plug fused at 5 A or…
Read the answer →22Kits with a battery fall outside the plug-in route because they can store energy, so treat them as ordinary fixed generation. Hardwire them by a…
Read the answer →23Use Type B where the inverter or PCE lacks at least simple separation between DC and AC and could feed smooth DC fault current, unless the…
Read the answer →24It is not mandatory, but MIS 3002 requires the MCS contractor to advise the customer on extra measures that improve durability and performance…
Read the answer →25Pitched-roof kits must be certified to MCS 012. Issue 3.0 has been mandatory since 10 May 2025. Hooks on tiles or slates must either put no load…
Read the answer →26Calculate string Voc at the lowest expected cell temperature using the module's Voc temperature coefficient and keep it below the inverter's…
Read the answer →27MIS 3002 requires a competent structural check. For trussed rafters, take 0.785 kN/m² dead load less the existing covering, or 0.75 kN/m² imposed…
Read the answer →28Usually yes. MIS 3002 says BS 7671 reg 443.4.1 applies: overvoltage protection is required where consequences are serious, and in all other cases…
Read the answer →29Yes. G98 and G99 thresholds use the inverter's AC Registered Capacity, not the array's DC kWp, so a 3.68 kW inverter can sit behind a larger array…
Read the answer →30A4 was published on 15 April 2026 and replaces A3 for new work from 15 October 2026. It adds Chapter 57 for stationary batteries, requires PAS…
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