Seaward PV System User Manual

Page 4

Page 4 of 4

Seaward Solar, 6304 Benjamin Road, Suit 506, Tampa, Florida 33634, USA.

Tel: (813) 886 2775 Email: [email protected] Web: www.seawardsolar.com

Rev 2: 15.02.2012

The methods for performing these tests are generally familiar to all electricians. However,

difficulties may arise if the technician is unaware of the extent to which PV circuits need to be
segmented and isolated for these tests to be performed properly. Therefore, it is important that

anyone performing these tests be specifically qualified with regard to PV systems.

Combinations of standard electrical test equipment can be used to complete the required tests, such

as a megohm meter paired with either a digital multimeter or a clamp meter. Increasingly,
specialized test equipment is available for PV applications. For example, the PV100 solar installation

test kit from Seaward Solar includes everything needed to test to IEC 62446: a continuity and
insulation resistance tester, a digital multimeter and a dc current clamp.

While IEC 62446 does not specify the order of the tests, there is logic behind the order that it

recommends. For example, if equipment is properly bonded to earth, then it is inherently safer to
work around in the event of a fault; and if polarity tests are not completed before functional tests
are performed, then equipment may be damaged at start-up due to reverse polarity or overvoltage.

Note that in the event that a test indicates a fault, the standard requires that all previous tests be

repeated after the fault is rectified. This is because the fault may have influenced earlier test
results.

The subsections related to the

specific dc circuit tests provide
instructions on how to perform the

verification tests, as well as how to
interpret the results. For example,

IEC 62446 describes two short-
circuit test procedures, the results

of which can be measured using
either an in-line or a clamp-on

ammeter. Similarly, two test
methods are provided for the PV

array insulation test, as well as a
recommended procedure and a

table for interpreting the results
(see Table 1).

Test Method

System Voltage (Voc

stc x 1.25)

Test Voltage

Minimum Insulation

Resistance

<120v

250v

0.5MΩ

120 – 500v

500v

1MΩ

Test Method 1

Separate tests to
Array positive and
Array negative

<500v

1000v

1MΩ

<120v

250v

0.5MΩ

120 – 500v

500v

1MΩ

Test Method 2

Array positive and
negative shorted
together

>1000v

1000v

1MΩ

Table 1: Insulation resistance test results are satisfactory, according to the test methods
and procedure outlined in IEC 62446, if they are not less than the values shown here.