Need help in recognizing Power Pole types and its components.?

Thread Starter


Joined Jan 23, 2009
Hi there,:(
I've been given this task to recognize the different types of power poles and their electrical equipments. The images are in the following link. I have encircled the equipments and components that are needed to be NAMED.

Please help me name these components and the types of poles.
I would be highly grateful...I'm really confused!:confused:
Thnx in advance.

Thread Starter


Joined Jan 23, 2009
Hi Bertus,
Thanks a lot for the reply. there are many other things than isolators in images C, E, F & G.
I'm quite confused what are things in the following circles:

red and green circles of C

green and pink circles of F
red circle of E
pink, green, yellow circles of G

thanks again!


The things you circled are isolators.
These can be made of glass or ceramics.



Joined Apr 5, 2008

The Red in C are isolation parts.
The Green in C are isolation parts with a something like a switch.
The Green and Pink in F also look like switches.
The Red in E are ceramic isolation parts.
The Pink and Green in G are isolators.
The Yellow in G looks like a switch.



Joined Apr 20, 2004
Just a note - the circled devices are called 'insulators' in English, although their purpose is to isolate the hot line from electrical contact with other conductors.


Joined Jan 16, 2008
Just to confuse matters the photos contain both insulators and isolators or to give them there proper names disconnect switches.

Insulators are used to physically attach the power cable to the pole while electrically isolating (insulating) the electricity from the pole.

Disconnect switches (or isolators) are used to cut power to a section of power line either to prevent overload or so that maintenance work can be performed.

Photo A power pole the red circled object is an insulator.
Photo B power pylon red & green = insulators.
Photo C power pole red = insulator, green = disconnect switch.
Photo D power pole red = insulator.
Photo E telegraph pole red = insulator.
Photo F power pole red = insulator, green & purple = disconnect switch.
Photo G power pole red, green & purple = insulators, yellow = disconnect switch.


Joined Apr 5, 2008

Thanks for correcting the naming of the parts.
I am dutch and we use isolator for something rigid that holds the cable at place without electrical contact.
A switch can be opened and closed.



Joined Nov 21, 2006
1. The red circles of c:
Porcelain insulators, often referred to by linemen as "bells". They are available in different diameters and different strain ratings. They are used here in "dead end" configuration, but the can also be used in suspension(vertical) situations as well. The bell insulator typically comes with a ball fitting on one end and a socket on the other allowing them to connected together for added insulation levels.

The green circles of C:
Appear to be arm mounted switches (load break type- that's the funny white appendage you see stickup up off to the side of each unit). These are used of course to create an open point in a circuit when needed. These appear to be in a circuit where it may be necessary to open while current is flowing. With normal switches (non- loadbreak type) this would be a definite NO-NO.

The green circles in F appear to be disconnect switches again with arc interrupting equipment fitted.
Judging by insulator size, the line voltage here probably is 20KV or higher.
I can't see in enough detail to be 100% sure, but I'd be willing to bet you a beer or two on it.

The pink circles in F are commonly referred to as fused cut outs. You will find these in use to connect the source line to say a transformer or where the line transitions from overhead to underground cables. They ARE NOT to be opened under load without the proper tools. The fuse should be sized properly to protect whatever is below the cutout.

The red circle of E:
Pin type insulators. The ones shown are typically used on lower voltage circuits (2400 volts etc.)
and even some old, OLD communications circuits used these. In the USA, there are still some of these in service along old runs of railroad tracks, etc. They may be glass, molded glass, or a hard composite/plastic type of material. Some folks collect these if in good condtion.

Pink circle of G:
Linemen commonly refer to these as lightning arresters, or surge arresters. They are usually installed close to where there is any equipment that needs to be protected from switching surges and of course lightning strikes. The ones pictured appear to be newer "polymer" type. They are very effective if installed properly, are relatively light weight and very long lasting.(unless blown to hell by a direct lightning hit)

Green circles of G:
Again a pin type insulator, porcelain, and very common on distribution circuits where the line to ground voltage is 4-10 KV.

Yellow circles of G:
A fused cutout. This time a polymer type. Holds a fuse of appropriate size to protect the transformer that it is connected to below. If the fuse blows, the "door" should drop open signaling the lineman that there is a problem.

If you are studying power lines, good for you! The world really needs good electrical workers.
If you are planning on getting up close to any of this stuff, DON'T.
Curiosity killed the cat, don't let it kill you...
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