Visual Recognition?

[ScottiSteve]

Hi folks,

I'm doing a power study just now and have come across a breaker/switch that I'm trying to find out a little more about. The problem with all the old equipment is that there isn't a lot of information floating around about them. Especially when the manufacturer doesn't make them any more!
So if anyone has seen this before or could tell me whether or not it is a switch or a CB that would be great. I would have said switch until I noticed the 'No overcrrent protection on this pole only sticker'

Photo linked.

Thanks,

Steve

 

[alehman]

The device on the right certainly appears to be a circuit breaker. Did you try Googling "merlin gerin ns160"?

 

[davidbeach]

It appears that the one on the left is a molded case switch, possibly no interrupting rating as such, but should have a withstand rating. Some molded case switches have a high set magnetic release at/near the withstand rating to avoid damage during faults, self protection only.

It appears that the one on the right is a 4 pole circuit breaker with a neutral pole on the left. The three poles on the right provide overcurrent protection, the neutral pole on the right only provides switching. The use of white for a phase conductor and black for the neutral looks just plain wrong, obviously not in the NEC world.

Presumably there is another circuit breaker off the picture to the lower right. No clue why anyone would want to switch the neutral. Unfortunately there appears not to be a ground and that is a safety concern.

 

[ScottiSteve]

Guys,

The breaker on the right is fine, I have the info I require on that one. It was just the one on the left of the picture, would have helped if I'd remember to specify that! ;-)
Thanks, I'll presume that the 225A Max rating then is just the self protection then and that it is in fact a main switch.
The ground, I would imagine, does come into the MCC but is terminated in the cable zone onto an earth bar o something similar.

 

[NCTHAI]

This is Switch only. No protection. Safe to assum that it is isolator.

 

[waross]

I see that the molded case switch also appears to be switching the neutral. If it is the neutral pole that has the "No protection on this pole only" sticker, I would assume that the sticker was meant to be applied when the neutral switch was used with a molded case breaker.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[rbulsara]

Why is this even a question? It says right on it it is a switch and no OCP.

The lable in neutral pole may mean it does not have even have magnetic protection which other poles would have in many MCS. I have not seen such lable before, someone may have stuck it on. Who knows, but why would it be a reason to believe it is not a switch only?

The 250A is just the maximum current carrying cpacity, like any other dumb switch. You cant use it for higher rated circuits or it will burn down (not open).

 

[jghrist]

If you'll notice, the phase conductors go thru the Merlin Gerin breaker, but the neutral conductors do not. This is the reason for the add-on "no protection" label for the neutral pole.