bigger 600A CT's or run in parallel?

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nycentral13
Posts: 8
Joined: Mon May 13, 2013 10:46 am

bigger 600A CT's or run in parallel?

Post by nycentral13 »

Hi Everyone,

I am connecting a Omnimeter II v.3 (3phase - 4wire) to a new Cummins diesel genset that puts out 600A per leg. I ordered the EMK 600A solid CT rings (only type offered by EKM for 600A) and these have a 45mm inner diameter. I am running three electrical cables in parallel for each phase (triple lugging 4/0 cable so a total of 9x hots, 3x neutrals and 1x ground) but my 4/0's wire has an outer diameter of 24mm. Pulling out my geometry book says that if the wire's was just a bit skinnier (20.8mm OD) I could fit three inside the 45mm CT, but alas, only one of the 24mm wires will now fit. Similarly, three 24mm wires fit inside a 52mm hole, so that is the minimum size I am looking for.

Is there a 600A 26.6mA CT ring available with a larger inner diameter? Rogowski coils? Or is my only solution to parallel three 600A CT's for each leg? I can't reduce the size of the wires and there is no other place to put the CT's where the diameter is smaller.

I saw paralleling CT's on another chat here on this forum:
http://forum.ekmmetering.com/viewtopic.php?f=8&t=3226

Kind thanks in advance,

Eric
Jameson
Posts: 860
Joined: Fri Nov 04, 2011 7:42 pm
Location: Santa Cruz, CA
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Re: bigger 600A CT's or run in parallel?

Post by Jameson »

Hello Eric,

Good question. While yes you could use 3 of the 600 amp CTs per phase (9 total), I would think it would be better and more economical to use either our 65mm Split Core 800 amp CT:
http://www.ekmmetering.com/split-core-c ... 5-800.html

Or our 80mm Solid Core 800 amp CT:
http://www.ekmmetering.com/solid-core-c ... 0-800.html

This way you can just use 1 CT per phase. You will have to use a USB converter and the EKM Dash software to change the CT ratio of your meter from 600 amps to 800 amps. It is fine to use an 800 amp CT on a 600 amp per phase system.

Hope this helps!
Jameson
EKM METERING
http://www.ekmmetering.com
831.425.7371
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