REC TwinPeak Series Installation Manual - UL 1703
Rev B - 03.15
Ref: NE-06-08-B
4
ELECTRiCaL iNSTaLLaTioN
ElECtRICal REQuIREmEnts
i) system Requirements
REC TwinPeak panels are only for use where they meet the specific technical requirements of the complete system. Ensure other components do not
cause mechanical or electrical damage to the panels.
ii) Connection
if panels are connected in series, they should have the same amp rating. if panels are connected in parallel, they should have the same voltage rating.
iii) string configuration
when using string configuration, plan and execute it according to inverter manufacturer’s instructions. The number of panels connected to an inverter
should be within the inverter voltage limits and operating range. Do not exceed the total system voltage permitted by the manufacturer, nor under any
circumstance exceed the maximum system voltage of 1000 v. The maximum reverse current is 15 a and the maximum series fuse rating is 15 a.
iv) wiring layout
To minimize voltage surges (e.g. indirect lightning strikes), cables of the same string should be bundled together so loops are as small as possible.
String configurations must be checked before commissioning. if open circuit voltage (v
oC
) and short circuit current (i
SC
) deviate from specification,
this may indicate a configuration fault. Correct DC polarity should be observed at all times.
v) Junction box, connectors and materials
The panel junction box is rated iP67, the connectors are rated iP67 only when correctly connected. all connectors and cables must be secure and
tight as well as electrically and mechanically sound. Uv-resistant cables and connectors approved for outside use must be used. Conductor gauge
must ensure DC power losses (voltage drop) are kept to a minimum (< 1%). observe all local regulations when selecting cables. For field connections,
use minimum 12 awg (4 mm²) or copper wires insulated for a maximum operating temperature of 90°C.
vi) Cable management
Cables must be secured using Uv-resistant cable ties or other sunlight-resistant device. Loose and unsecured cables should be protected from
damage (e.g. mechanical, abrasion, sharp objects, animals). as far as possible, avoid exposing cables to direct sunlight and permanent tension.
REC prohibits any modification to the panel, including the cutting of cables in order to change the connector type or the opening of the
junction box unless explicitly authorized by REC. Doing so will invalidate the warranty.
vii) Electrical Ratings
Under normal conditions, a photovoltaic panel is likely to experience conditions that produce more current and/or voltage than reported at STC. The
requirements of the National Electric Code (NEC) in article 690 must be followed to address these increased outputs. in installations not under the
requirements of the NEC, the values of i
SC
and v
oC
marked on the panels must be multiplied by a factor of 1.25 when determining component voltage
ratings, conductor ampacities, overcurrent device ratings and size of controls connected to the Pv output.
safEty mEasuREs
wiring installation shall be in accordance with the NEC (or CSa C22.1, Safety Standard for Electrical installations, Canadian Electrical Code, Part 1
where applicable). all relevant electrical installation codes and regulations should be observed for regulations on working at heights and fall protection.
i) safety in the working area
installation of REC TwinPeak panels may involve working on a roof. Ensure all local regulations regarding working at heights are followed. before
beginning work on a photovoltaic system, ensure all working surfaces are structurally sound and capable of bearing the weight of employees and
required equipment. Remember to isolate the system from the grid before carrying out any maintenance or repair work.
ii) preventing current generation
Solar panels automatically generate current (electricity) when exposed to light. To prevent this, shield the system with a non-transparent cover during
installation, maintenance or repair work.
ii) specific hazards of DC electricity
Solar panels generate direct current (DC). once current is flowing, breaking or opening a connection (e.g. removing a DC cable from the inverter) can
cause an electrical arc. Unlike low voltage aC wiring, DC arcs are not self-extinguishing. They are potentially lethal burn and fire hazards, capable of
high temperatures that can destroy contacts and connectors:
•
Follow panel and inverter manufacturers’ installation, handling and operating instructions
•
Remove/open the inverter aC fuse/circuit breaker before disconnecting from the public grid.
•
Switch off or disconnect the inverter and wait for the time specified by the manufacturer before commencing work. High-voltage components
need sufficient time to discharge.
iv) safety requirements
The voltage produced by a single panel and panels connected in series (voltages added together) or in parallel (currents added together) can be
dangerous. although the fully insulated plug contacts on the panel’s output cables provide touch-safe protection, the following points must be
observed during handling to avoid the risk of sparking, fire hazards, burns and lethal electric shocks.
•
Exercise extreme caution when wiring panels and look out for damaged or dirty cables etc.
•
Never insert metallic or other conductive objects into plugs or sockets.
•
Ensure that all electrical connections are completely dry before assembly.
•
keep all materials, tools and working conditions dry and tidy.
•
Use appropriate safety equipment e.g. nonslip footwear, insulated gloves and insulated tools.
•
Solar panels produce current when exposed to sunlight. Do not connect the system to the inverter during solar exposure.
