Mastech MS5908C User Manual

MS5908C

Circuit Analyzer

User’s Manual

Ω

TEST

mA
VA
ms

Hz%

VA

ms

%

AC

L - N

L - E

N - E

Peak

Z - L

Z - N

Z - E

ASCC

5 A 8 A 10 A

HOLD

N

E

L

V Vd Z

RCD

GFCI

[]

[]

MS5908C

01 02

General Instructions

This ci rcuit ana lyzer is a sp ecial tes t device
desig ned for AC low -voltag e distrib ution lin e quick
fault l ocation . With simp le operat ion, accu rate
measu rement an d other fea tures, it c an detect
multi ple probl ems on a line , such as cau sing to
elect ric shock , electri cal fire, a bnormal o peratio n
of equi pment, et c.

Functions:

• TRMS me asuring AC v oltage

• Artif icial loa d 5A, 8A, 10A me asuring l ine drop

• Measu ring phas e voltage , neutral l ine (zero l ine)

volta ge to earth , peak volt age, freq uency

• Measu ring phas e (live lin e), neutr al line (ze ro line),
earth l ine condu ctor impe dance

• Ident ifying 3- wire sock et connec tion mode ( zero
for lef t and live fo r right, ha ving eart h line or not )

• Test the re liabili ty of resid ual curre nt device ( RCD)
and res ponse act ion time

• Test the re liabili ty of GFCI ac tion and re sponse
actio n time

• Backl ight func tion and da ta hold fun ction

Warning

Do not us e this inst rument wi thout rea ding,
under standin g and follo wing the in structi ons
in this m anual. Re ad and foll ow them car efully,
as well a s all warni ngs and ins tructio ns marked
on the in strumen t!
To prev ent damag es to the ins trument , it should
not be us ed for meas uring the o utput of UP S
equip ment, nor f or measur ing adjus table lig ht
and squ are wave ge nerator !
For mea suremen t accuren cy during r epeated
usage , allow at le ast 30 seco nds betwe en two
conse cutive me asureme nts to faci litate
equip ment cool ing when me asuring v oltage
drop an d cable imp edance.
To ensu re accura te measur ement dat a, please
check w hether th ere is impo rtant loa d or heavy
load in t he line bef ore testi ng. Turn of f the heavy
load, i f necessa ry, then re test.

05 06

L - N N - E

Peak

Volta ge (V ): real t ime displ ay of cable c onnecti on

statu s and displ ay the volt age drop of c urrent lo ad
and mea suremen t results o f phase vol tage drop
TRMS. This test i tem inclu des 3 subme nus, name ly
load wi th 5A, 8A and 10 A. Press Up “ ” or Down
“ ” selec tion key on t he sub test i tem to ente r the
relev ant test it em.
One ana log load ca n be added to l ive line (p hase
line) a nd zero lin e (neutra l line) for t he analys er
to meas ure the vol tage drop , and then ca lculate t he
volta ge drop of 5A , 8A and 10A load s eparate ly.
Under t he approp riate tes t functio n, press th e test
key “ ” to te st.

d

Menu Operation

The mai n test item s of the anal yser are lo cated on
the bot tom of disp lay, incl uding fiv e test item s,
namel y: voltag e (V), volt age drop (V d),
imped ance (Z), R CD and GFCI . Press the m ain test
item se lection k ey “ ” to selec t relevan t test item .

V Vd Z

RCD

GFCI

Volta ge (V): rea l time disp lay of TRMS of pha se

volta ge, wirin g status an d frequen cy. This test it em
inclu des 3 subme nus, name ly phase vo ltage (L_ N)
TRMS, v oltage to e arth of neu tral line ( zero line )
(N_E) TRMS, pea k voltage ( Peak). Pr ess Up “ ”
or Down “ ” selecti on key on the s ub test ite m to
enter t he releva nt test ite m.

Pre ss “FUN C”Pre ss “FUN C” Pre ss “FUN C”

Pre ss “FUN C”

Pre ss “FUN C”

Press

“ ”

Pres s

“ ”

Pres s

“ ”

Pres s

“ ”

Pres s

“ ”

Press

“ ”

11 12

Wir i ng te s t

N

E

L

The wi ring test r esult wil l be shown im mediate ly
after t he analyz er is plugg ed to the soc ket under
test. The analy zer can ide ntify the f ollowin g wiring
condi tions and d isplay th e test resu lt on the scr een.

Wirin g
condi tion

Norma l

No grou nd
wire is f ound

The liv e/zero
line is

conne cted
inver sely.

Other
condi tions

Scree n display

L E N

Capti on

Off

On

Flashing

Where a ny wiring a bnormal ity is foun d, the
analy zer can onl y complet e partial m easurem ent.
Where t here is no ea rth line, t he analyz er can only
measu re the phas e voltage a nd voltag e drop.

Notes: The analyzer can't detect

1. Circ uit volta ge, i.e. th e voltage b etween tw o live
lines ;

2. Comb ined faul t;

3. Reve rse conne ction of ea rth line an d neutral l ine.

Voltage measurement

The no rmal meas ured valu e of phase vo ltage is
220V± 10%, 50Hz . The peak v oltage of s ine-wav e
alter nating cu rrent is 1. 414 times t o the effe ctive
value o f phase vol tage. Th e voltage t o earth of
neutr al line sha ll be less th an 2V. In the sing le-phas e
circu it, if the “v oltage to e arth of zer o line” is hi gh,
it indi cates tha t the leaka ge curren t in zero lin e or
earth l ine is high . In the thre e-phase c ircuit wi th
neutr al line, a hi gh “volta ge to earth o f zero line ”
indic ates that t he three- phase loa d is imbala nced
or the ne utral lin e is affec ted by harm onic
inter ference . Excessi ve voltag e (voltag e to earth
of zero l ine) will r esult in ru nning dev iation or
inter ruption .

15 16

Voltage drop (V ) measurement

Dummy l oad shall b e used in the c ircuit to
measu re the load p hase volt age and the n calcula te
the vol tage drop . The volt age drop an d load phas e
volta ge will be di splayed w hen the loa d reaches
5A, 8A and 1 0A.
In term s of qualif ied circu it, when me asureme nt
is made i n the most re mote sock et from the
switc hboard, t he voltag e drop shal l be less tha n 5%.
Durin g the measu rement of t he remain ing socke ts
of the sa me area, th e farthes t socket fr om the
switc hboard sh all be meas ured firs t and then ot her
measu rements s hall be mad e from the di stant to
the nea r. The read ing of the vo ltage dro p shall be
shown o n the downw ard trend .
If the vo ltage dro p exceeds 5 % and no obvi ous
drop of r eading is f ound duri ng the meas urement
made ne ar the swit chboard , it indica tes that th e
first c onnecti on point go es wrong. I n this case ,
perfo rm a visual i nspecti on of the wir e connect ion
among t he first co nnectio n point, eq uipment a nd
switc hboard an d the conne ction of br eaker
(air- break swi tch). Usu ally, a hig h impedan ce point
gener ates heat . To locate th is proble m, infrar ed
radia tion ther mometer c an be used. I n additio n, we
can dir ectly mea sure the vo ltage on bo th sides of
the bre aker (air -break sw itch) to lo cate the po int of
failu re.

d

If the vo ltage dro p exceeds 5 %, and duri ng the
measu rement ma de near the s witchbo ard, the
readi ng drops co nstantl y and no obvi ous chang e
is foun d between t he two sock ets, it ind icates th at
the lea d wire diam eter is too s mall comp ared with
the tra nsmissi on distan ce, the tra nsmissi on
dista nce is too lo ng or the cir cuit is ove rloaded .
Under s uch circu mstance s, check th e cable to se e
if the le ad wire dia meter com plies wit h the requi red
stand ard, and me asure the l ead wire cu rrent to se e
if it is ov erloade d.
If the vo ltage dro p exceeds 5 % and there i s an
obvio us change o f voltage d rop readi ng betwee n
the two s ockets, i t indicat es that a hig h impedan ce
point e xists bet ween the tw o sockets . Usually,
probl ems are fou nd at the con tact, suc h as poor
conne ction, lo ose conne ctor, or soc ket probl em.

19 2 0

Fault localization and trouble shooting

Measurement

Item

Normal

measurement

result

Fault

measurement

result

Possible

cause

Trouble

shooting

Conductor

impedance

for

live line

and

zero line

The

impedance

is

too high

Redistribute

the

circuit load.

The circuit

is overloaded.

Check the

wire diameter

and

rearrange

the wire

accordingly.

High

impedance

point exists in

the circuit

or

switchboard.

Locate the

high

impedance

and repair

or replace

the parts

The wire

diameter is

too small

for the power

transmission

length.

Check

the wire

diameter and

rearrange

the wire

accordingly.

Locate

the high

impedance

and repair
or replace

the parts

The wire

diameter is

too small

for the power

transmission

length.

High
impedance
point exists

in the circuit

or

switchboard.

The

impedance

is

too high

Conductor

impedance

for

earth line

For

personnel

safety

<1Ω

For

equipment

safety

<0.25Ω

No. 14 line

(2.0mm )

<0.15Ω/m

No. 12 line

(3.3mm )

<0.1Ω/m

No. 10 line

(5.2mm )

<0.03Ω/m

Residual current device (RCD) test

Durin g the RCD tes t, the anal yzer will g enerate a
low cur rent betw een live li ne and eart h line by
means o f a fixed res istance , which wil l affect t he
curre nt balanc e between l ive line an d zero line .
Accor ding to UL, t his curre nt trigge r shall be le ss
than 30 mA. The RC D shall res ponse to th e current
imbal ance by cut ting off t he power. The ana lyzer
will di splay the v alue of the c urrent tr iggered ( mA)
and res ponse tim e (ms).
The wor d “TEST” wi ll be displ ayed when t he button
“ ” is pres sed, whic h means the t est is in the
proce ss. RCD sha ll be trigg ered with in the spec ified
index t o cut off th e power of th e circuit u nder test .
If the RC D fails to be t riggere d, the anal yzer will
stop te sting aut omatica lly after 6 .5 second s.
Analy sis on RCD sh all be made a ccordin g to the
test re sult to see i f it goes wro ng, is inst alled
prope rly or prot ects the ci rcuit effective ly.

Notes:

1. Chec k the circu it to see if th ere is heav y load over
the cir cuit befo re testin g and, if nec essary, turn
off th e load to avo id wrong te st result .

2. Eart h connect ion is requ ired when t he RCD is
teste d in the 2-wi re system ( without e arth line ). .

2

2

2

25

00-05-2999

1) The analyzer is powered by six AAA batteries.

2) Cut off the power and pull out the test line.

3) Unscrew the battery compartment and open the cover.

4) Replace the batteries.

5) Ensure the batteries are installed properly
(Do not mismatch polarity)

6) Put back the cover and tighten the screws.

Maintenance

Batte ry instal lation an d replace ment:

Clean ing:

Use soft cloth and neutral cleanser to clean the housing.
Use of abrasive or organic solvent is not allowed.