CT ratings

[27hillcrest]

I looked at a job that had a CT can and 4 discos hanging off. The CT's said 5-200 on them. I believe this would mean they were 400amp CT's. The customer is wanting to change out all the discos and got to one main panel board. Not knowing the calculated load for the building and using the CT ratings to install a 400amp mains service. Would this make sense to anyone. The 4 discos are:
1-300amp
1-175amp
1-225amp
1-175amp
Thanks,

 

[LarryFine]

They sound like 200a CT's to me.

No, I would never guess like that.

 

[iwire]

5 - 200 would be the ratio and the upper limit

Ratio

The ratio of a current transformer refers to the turns ratio of the windings. For example, a

200/5 transformation is equivalent to a 40 to 1 ratio. (200 divided by 5 is 40). The secondary of a CT is always stated to be 5 amps at the rated primary winding current.

 

[iwire]

No, I would never guess like that.

Neither would I, we would install a recoreding meter on the service if we could not get demand info from the power company.

 

[djohns6]

200/5 perhaps ? 200 primary amps equals 5 amps secondary . Or 40 to 1 .

Can you read the CT nameplate ?