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power line to a cctv camera 12v

Z

zaa

I got three cameras i bought for surveillance and I got a power bo
(12vdc 4 output 2 amp). I got 100ft cables for each camera with tw
lines joined to getther (video and power) In order to connect the powe
to the power box, i had to cut open the wire. It wasnt red and black a
i hoped, so I can tell which is positive and negative. Instead the tw
wires consisted of an inner wire in the middle with insulation an
naked wire around it on the outside, the entire thing has an oute
insulation coating.I just need to know which is positive I think th
sales guy said the middle wire withthe coating is neutral and the oute
is negative. I just want to be sure. and any tips on the proper way t
attach wire to + and - screws on the power box? since they are ver
thin wires (carry 12 v) sorry for the essa
 
N

NN

You already know that you have a 50% chance of being right if you
guessed. General rule (but not an answer) is the outer insulation is
usually negative (negative is less guarded from exposure, older cars
carried negative current in all its metal parts). But before I turn
this into a essay, look at where the wires are sodered to and see if
there is a + sign for positive and - or ground text or grd abvr. for
negative and that would be a foolproof answer.
 
J

James Sweet

zaa said:
I got three cameras i bought for surveillance and I got a power box
(12vdc 4 output 2 amp). I got 100ft cables for each camera with two
lines joined to getther (video and power) In order to connect the power
to the power box, i had to cut open the wire. It wasnt red and black as
i hoped, so I can tell which is positive and negative. Instead the two
wires consisted of an inner wire in the middle with insulation and
naked wire around it on the outside, the entire thing has an outer
insulation coating.I just need to know which is positive I think the
sales guy said the middle wire withthe coating is neutral and the outer
is negative. I just want to be sure. and any tips on the proper way to
attach wire to + and - screws on the power box? since they are very
thin wires (carry 12 v) sorry for the essay


That's coax, generally the middle wire is signal and the outer shield is
ground. You need to use propper connectors to splice coax or your
picture will suffer, though with security cameras you can probably cheat
and just solder splice the wires and tape the joints and not notice.
 
A

Arfa Daily

James Sweet said:
That's coax, generally the middle wire is signal and the outer shield is
ground. You need to use propper connectors to splice coax or your picture
will suffer, though with security cameras you can probably cheat and just
solder splice the wires and tape the joints and not notice.

If it's two joined together, then it's probably " figure 8 " audio screened
cable. In general, the centre conductor will have been designated " + " and
the outer shield, ground ( " - " ) but this is only a convention, and not
set in stone. If the other cable is the ' video out ', then with 99%
certainty, the screen of that one, will be ground. If you then measure with
an ohm-meter between the two shields, and they read shorted together, then
you can be pretty much certain that the shield of the power cable is " - "
and the centre, " + ".

To join to the screw terminals, you can un-plait the screen, and twist it
back into a pigtail, slip a bit of sleeving over it, and treat it as a
normal wire, or solder and sleeve a pair of thicker wires to the thin ones
or, best solution, solder the inner, and pigtailed screen, to solder tags,
which can then be firmly screwed to the power unit.

Arfa
 
Z

zaa

James said:
zaa wrote:
I got three cameras i bought for surveillance and I got a power box
(12vdc 4 output 2 amp). I got 100ft cables for each camera with two
lines joined to getther (video and power) In order to connect th
power
to the power box, i had to cut open the wire. It wasnt red and blac
as
i hoped, so I can tell which is positive and negative. Instead th
two
wires consisted of an inner wire in the middle with insulation and
naked wire around it on the outside, the entire thing has an outer
insulation coating.I just need to know which is positive I think the
sales guy said the middle wire withthe coating is neutral and th
outer
is negative. I just want to be sure. and any tips on the proper wa
to
attach wire to + and - screws on the power box? since they are very
thin wires (carry 12 v) sorry for the essay




That's coax, generally the middle wire is signal and the outer shiel
is
ground. You need to use propper connectors to splice coax or your
picture will suffer, though with security cameras you can probabl
cheat
and just solder splice the wires and tape the joints and not notice.

thanks for that info but other than a 'wiring simplified' book I go
from home depot, I know next to nothing about splicing..could yo
explain what you meant by proper connectors, the video line is fine i
has bnc connection on both ends. I need to connect the power so yareyo
saying the inside wire is negative and the outside is positive
 
Z

zaa

Arfa said:
"James Sweet" [email protected] wrote in message
zaa wrote:
I got three cameras i bought for surveillance and I got a power box
(12vdc 4 output 2 amp). I got 100ft cables for each camera with two
lines joined to getther (video and power) In order to connect th
power
to the power box, i had to cut open the wire. It wasnt red and blac
as
i hoped, so I can tell which is positive and negative. Instead th
two
wires consisted of an inner wire in the middle with insulation and
naked wire around it on the outside, the entire thing has an outer
insulation coating.I just need to know which is positive I think the
sales guy said the middle wire withthe coating is neutral and th
outer
is negative. I just want to be sure. and any tips on the proper wa
to
attach wire to + and - screws on the power box? since they are very
thin wires (carry 12 v) sorry for the essay




That's coax, generally the middle wire is signal and the outer shiel
is
ground. You need to use propper connectors to splice coax or you
picture
will suffer, though with security cameras you can probably cheat an
just
solder splice the wires and tape the joints and not notice.

If it's two joined together, then it's probably " figure 8 " audi
screened
cable. In general, the centre conductor will have been designated " +
and
the outer shield, ground ( " - " ) but this is only a convention, an
not
set in stone. If the other cable is the ' video out ', then with 99%
certainty, the screen of that one, will be ground. If you then measur
with
an ohm-meter between the two shields, and they read shorted together
then
you can be pretty much certain that the shield of the power cable is
- "
and the centre, " + ".

To join to the screw terminals, you can un-plait the screen, and twis
it
back into a pigtail, slip a bit of sleeving over it, and treat it as a
normal wire, or solder and sleeve a pair of thicker wires to the thi
ones
or, best solution, solder the inner, and pigtailed screen, to solde
tags,
which can then be firmly screwed to the power unit.

Arfa
just so I understand you are describing the power cable right (its tw
cables joined together, split up on the ends, one has bnc connection o
both ends goes from camera to the DVR the other is the power which i
what I am trying to connect to the power box. )
When you said un plait i guess youmeant taking off the coating, I wa
planning to twist the wires (i didnt mention that they are both lik
vermicelli or very thin strands of hair and not one piece of copper an
also the outer wire is about 3 times thicker than the middle insulate
one)
and the solder tags I guess would have to be small enough to fit in th
power box (not a lot of space and would need 4 tags)
 
J

Jumpster Jiver

zaa said:
I got three cameras i bought for surveillance and I got a power box
(12vdc 4 output 2 amp). I got 100ft cables for each camera with two
lines joined to getther (video and power) In order to connect the power
to the power box, i had to cut open the wire. It wasnt red and black as
i hoped, so I can tell which is positive and negative. Instead the two
wires consisted of an inner wire in the middle with insulation and
naked wire around it on the outside, the entire thing has an outer
insulation coating.I just need to know which is positive I think the
sales guy said the middle wire withthe coating is neutral and the outer
is negative. I just want to be sure. and any tips on the proper way to
attach wire to + and - screws on the power box? since they are very
thin wires (carry 12 v) sorry for the essay
Your safest bet is to buy an inexpensive voltmeter at Rat Shack or an
automotive parts store. Connect the wires to the meter's leads.
Connect the center wire to the red lead and the outer shield to the
black lead.
Measure the voltage with the meter.
If the voltage read POSITIVE 12V then the center lead is positive.
If it reads negative 12V then the center lead is negative.

Buying a $20 meter is cheaper than damaging your cameras by connecting
them backwards.
They SHOULD be protected against reverse polarity, but just in case, the
meter would be a wise investment.
 
R

Ryan Weihl

zaa said:
I got three cameras i bought for surveillance and I got a power box
(12vdc 4 output 2 amp). I got 100ft cables for each camera with two
lines joined to getther (video and power) In order to connect the power
to the power box, i had to cut open the wire. It wasnt red and black as
i hoped, so I can tell which is positive and negative. Instead the two
wires consisted of an inner wire in the middle with insulation and
naked wire around it on the outside, the entire thing has an outer
insulation coating.I just need to know which is positive I think the
sales guy said the middle wire withthe coating is neutral and the outer
is negative. I just want to be sure. and any tips on the proper way to
attach wire to + and - screws on the power box? since they are very
thin wires (carry 12 v) sorry for the essay

google google

" cctv camera power connection "

rw
 
A

Arfa Daily

Jumpster Jiver said:
Your safest bet is to buy an inexpensive voltmeter at Rat Shack or an
automotive parts store. Connect the wires to the meter's leads.
Connect the center wire to the red lead and the outer shield to the black
lead.
Measure the voltage with the meter.
If the voltage read POSITIVE 12V then the center lead is positive.
If it reads negative 12V then the center lead is negative.

Buying a $20 meter is cheaper than damaging your cameras by connecting
them backwards.
They SHOULD be protected against reverse polarity, but just in case, the
meter would be a wise investment.

That makes no sense against what the poster was asking ...

Arfa
 
A

Arfa Daily

zaa said:
just so I understand you are describing the power cable right (its two
cables joined together, split up on the ends, one has bnc connection on
both ends goes from camera to the DVR the other is the power which is
what I am trying to connect to the power box. )
When you said un plait i guess youmeant taking off the coating, I was
planning to twist the wires (i didnt mention that they are both like
vermicelli or very thin strands of hair and not one piece of copper and
also the outer wire is about 3 times thicker than the middle insulated
one)
and the solder tags I guess would have to be small enough to fit in the
power box (not a lot of space and would need 4 tags)?

I think that we must be misunderstanding exactly what your cable looks like.
The section with the BNC on each end, must be some kind of concentrically
constructed cable - either coax or some other kind of screened cable, but
that's neither here nor there.

I, and I think other posters, were assuming that the second ( power ) cable
was also some kind of concentric cable, with a central insulated conductor,
surrounded by an uninsulated braided shield, surrounded by an outer plastic
jacket. That's what it sounded like you were describing. If this were the
case, then by " un-plaiting ", I was referring to first exposing the braid,
by removing the outer jacket for a short distance, and then ' unpicking '
the exposed braid until its just a bunch of individual strands surrounding
the inner insulated conductor, then pulling all those strands together, and
off to one side, so that they can be twisted together to form a ' wire '.

Does this sound like what you have as a power cable ? How is this cable
terminated at the camera end ?

Arfa
 
Z

zaa

Arfa said:
"zaa" [email protected] wrote in message

Arfa Daily Wrote:
"James Sweet" [email protected] wrote in message
zaa wrote:
I got three cameras i bought for surveillance and I got a power box
(12vdc 4 output 2 amp). I got 100ft cables for each camera with two
lines joined to getther (video and power) In order to connect the
power
to the power box, i had to cut open the wire. It wasnt red and black
as
i hoped, so I can tell which is positive and negative. Instead the
two
wires consisted of an inner wire in the middle with insulation and
naked wire around it on the outside, the entire thing has an outer
insulation coating.I just need to know which is positive I think the
sales guy said the middle wire withthe coating is neutral and the
outer
is negative. I just want to be sure. and any tips on the proper way
to
attach wire to + and - screws on the power box? since they are very
thin wires (carry 12 v) sorry for the essay




That's coax, generally the middle wire is signal and the outer shield
is
ground. You need to use propper connectors to splice coax or your
picture
will suffer, though with security cameras you can probably cheat and
just
solder splice the wires and tape the joints and not notice.

If it's two joined together, then it's probably " figure 8 " audio
screened
cable. In general, the centre conductor will have been designated "
"
and
the outer shield, ground ( " - " ) but this is only a convention, and
not
set in stone. If the other cable is the ' video out ', then with 99%
certainty, the screen of that one, will be ground. If you the
measure
with
an ohm-meter between the two shields, and they read shorted together,
then
you can be pretty much certain that the shield of the power cable i
"
- "
and the centre, " + ".

To join to the screw terminals, you can un-plait the screen, an
twist
it
back into a pigtail, slip a bit of sleeving over it, and treat it a
a
normal wire, or solder and sleeve a pair of thicker wires to the thin
ones
or, best solution, solder the inner, and pigtailed screen, to solder
tags,
which can then be firmly screwed to the power unit.

Arfa
just so I understand you are describing the power cable right (it
two
cables joined together, split up on the ends, one has bnc connectio
on
both ends goes from camera to the DVR the other is the power which is
what I am trying to connect to the power box. )
When you said un plait i guess youmeant taking off the coating, I was
planning to twist the wires (i didnt mention that they are both like
vermicelli or very thin strands of hair and not one piece of coppe
and
also the outer wire is about 3 times thicker than the middl
insulated
one)
and the solder tags I guess would have to be small enough to fit i
the
power box (not a lot of space and would need 4 tags)?


--
zaa

I think that we must be misunderstanding exactly what your cable look
like.
The section with the BNC on each end, must be some kind o
concentrically
constructed cable - either coax or some other kind of screened cable
but
that's neither here nor there.

I, and I think other posters, were assuming that the second ( power
cable
was also some kind of concentric cable, with a central insulate
conductor,
surrounded by an uninsulated braided shield, surrounded by an oute
plastic
jacket. That's what it sounded like you were describing. If this wer
the
case, then by " un-plaiting ", I was referring to first exposing th
braid,
by removing the outer jacket for a short distance, and then ' unpickin
'
the exposed braid until its just a bunch of individual strand
surrounding
the inner insulated conductor, then pulling all those strands together
and
off to one side, so that they can be twisted together to form a ' wir
'.

Does this sound like what you have as a power cable ? How is this
cable
terminated at the camera end ?

Arfa

sorry for the later reply, your description is pretty accurate see link
below, I can not find any pics showing the inside of the power cable,
but it has a barrel i think at that end and the video has a bnc
connection at both ends. I have read about using power jacks and
adapters which seem to to be easier than soldering whicH I know I will
be doing someday but I dont have to time to neither buy the equipment
nor learn how to solder. Anyway, I also heard that its not good to use
tape ? One cctv says he always splices his connections any tips or
thoughts?
http://www.mjelectronics.com/pages/videoaccessories/cable.html
 
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