Yingli Solar PV Modules, Installation and User Manual
page 4
Grounding Holes
ø0.236in (6mm)
PV Laminate
Backing Nut
Toothed Lock Washer or KEPS Nut
Cup Washer
Aluminum
Frame
Screw
Equipment
Grounding
Conductor
Figure 7-1: Electrical circuitry of cells and bypass diodes
Figure 7-2: Electrical circuitry of cells and bypass diodes
In the event of a known or suspected diode failure, installers or maintenance
providers should contact the company the PV modules were purchased from.
Never attempt to open the junction box of a Yingli Solar PV module yourself.
PV Array Grounding
For optimal performance, Yingli Solar recommends that the negative pole of the
PV array be connected to ground.
Equipment Grounding
The frame of the PV module, as well as any exposed non-current-carrying metal
parts of fixed equipment that are able to become energized by the PV system,
must be connected to the equipment grounding conductor (EGC) in order to
prevent electrical shock. Even when applicable regulations, code requirements,
and standards do not require safety-related grounding, Yingli Solar recommends
grounding all PV
module frames in order to ensure the voltage between
electrically conductive equipment and earth ground is zero in all circumstances.
Proper equipment grounding is achieved by bonding all exposed non-current-
carrying metal equipment continuously to one another using an appropriately
sized EGC or racking system that can be used for integrated grounding (see
Option B in Grounding Methods below).
Yingli Solar PV modules employ a coated aluminum frame for corrosion
resistance. In order to properly ground the module frame, the coating must be
penetrated.
The potential for corrosion due to the electrochemical action between dissimilar
metals in contact is minimized if the electrochemical voltage potential between
the dissimilar metals is low. The grounding method must not result in the direct
contact of dissimilar metals with the aluminum frame of the PV module that
will result in galvanic corrosion. An addendum to UL Standard 1703 “Flat Plate
Photovoltaic Modules and Panels” recommends metal combinations not exceed
an electrochemical potential difference of 0.5 Volts.
The frame rails have pre-drilled holes marked with a grounding sign, as
illustrated in Figure 8. These holes should be used for grounding
purposes and
must not be used for mounting the PV modules. Do not drill additional holes
into the frame rails.
Figure 8: Grounding hole detail
The following grounding methods are available:
Option A: Screw Assembly (see Figure 9)
1. A grounding screw assembly must be attached at a designated grounding
hole location using only stainless steel hardware. Insert an M5 stainless
steel screw first through the stainless steel cup washer, and then through the
grounding hole.
2. Loosely engage a stainless steel backing nut and toothed lock washer to the
screw.
3. Bend the EGC into an omega (Ω) shape to tightly fit between the partially
installed screw head and cup washer. The EGC shall be exclusively in contact
with stainless steel.
4. Tighten the screw to 2.3 N∙m torque. The toothed lock washer should be
visibly engaged to the frame.
5. Route the appropriately sized EGC in such a way as to avoid contact with the
aluminum module frame.
Figure 9: Grounding screw assembly detail
Option B: Racking Manufacturer Integrated
Grounding Methods
Yingli Solar PV modules can be grounded by bonding PV modules to a grounded
racking system. Integrated grounding methods must be certified for grounding
PV modules and must be installed in accordance with the specified instructions
of their respective manufacturers.
Option C: Additional Third-party Grounding Devices
Yingli Solar PV modules can be grounded using third party grounding devices so
long as they are certified for grounding PV modules and the devices are installed
according to the manufacturer’s specified instructions.
M E C H A N I C A L I N S TA L L AT I O N
General
Yingli Solar PV Modules have been certified for a maximum static load on the
back of the module of up to 2400 Pa (i.e. wind load) and a maximum static load
on the front of the module of up to either 2400 Pa or 5400 Pa (i.e. wind and
snow load), depending on the module type (please refer to the data sheet for
Figure 7-1: Electrical circuitry of cells and bypass diodes
