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Yup, already talked to our system engineer and we do have to replace the 5A Cts. Thanks for the input guys!!!

Hi guys, our power transformers, 6.6kV/433V needs to be protected against restricted earth fault (87N) and standby earth fault (51G) and is connected in a 6.6kV HV switchgear. at the onset of the project all the secondary winding of the protection ct is 5A. There was a change in the design of...

thank you thruthefence! will open these links later.

Hi guys, We were tasked to design an offshore platform with helideck. Client specified in the bid work (but without a specification)that a Helicopter Starting/charging system be installed in the platform with a battery system of 28.8volts & 420Ah (ampere-hour). Our predicament is that there is...

EEJaime Seldom do I see a proposal like this, some client prefers a single breaker configuration (for HV). Mostly I saw are on LV switchgears and MCC. rcwilson, Thats what Iam afraid of, compartments getting crowded. It will be up to the client to decide since there were a few loopholes...

Hi jghrist, Basically, out here for an HV switchgear, the vertical panel (w/c is compose of 2 or 3 section or cubicle)are called compartment. You're right it is two separate compartment and a metering and instrumentation compartment/cubicle between them. So the setup is 1-VCB in the upper...

ppedUK thanks for the comments. Personally too, I don't like the setup. Installation, maintenanace and safety aspects is a bit questionable becoz of too tight a space. Appreciate your help.

Hello scotty & slavag Thanks for the advise. Anyway just starting the evaluation and I haven't seen yet a 2 VCB's in a single compartment. Mostly are single CB per compartment. I guess I've to ask them about the installation, maintenance and safety aspects of the equipment since its going to...

Hello again guys, I'm evaluating an ABB Unigear 6.6kV HV switchgear (well our client considers the 6.6kV as a high voltage) and I'm quite a bit puzzled by their offer. ABB is offering a 2-tier double level switchgear, meaning the upper and lower panels of the switchgear compartment can be...

Slavag, waross & nawao appreciate your help!!!! Thanks guys!

Hi guys, just wanted to ask if my new gas turbine generator rated 11500kW, 6.6kV, 3phase, 50Hz, with an NGR can be paralleled with the existing GTG of 10800kW 6.6kV, 50Hz, 3phase, 50Hz also with an NGR. These gen set are use on offshore platforms. Instrumentation, control and synchro of the...

"I'm trying to find the best way to patch a hole in a NEMA 4x panel box." "The Stat sensor is an open device and a gasket behind the stat would not properly shield the hole from the outside environment" I am not quite sure of your question, but are you trying to "fix/patch/repair" a NEMA 4X...

cha1n, jraef is right. this is all about safety! whether its human , property, etc. you still have to follow the existing code of your country and locality. since you are in UK i believe you should be using the IEC. and yes, scottyUK can sure help you. and remember " a little knowledge is a...

it seem to me that the design of your switchgear and its downstream emergency lighting DB are not properly designed, thats why you have a voltage drop on your emer. lighting DB.

sparky, i believe it would be best to look it up in the NEC(?) by yourself. and pose your question here if you are in doubt at the same time referring to what section in the NEC. These guys also have their on work and they have no time to research it for you. :)

Hi, This one seems a bit late too. Most of the time UPS feeds vital instrument loads (for safe shutdown of the process) and telecommunications. And yes, if "all" instrument are fed via hydraulic or pneumatic controls then UPS will not be considered. HMI or PC/LAN servers will be using...

You derate cables in group installation (bundle) and you also derate cables for various ambient temperature whether it is in ground (buried) or in air (cable trays, etc).

I agree with dpc and waross, you need to familiarize your self with your local electrical code. also familiarize with clients specs (i.e single core/multi core, XLPE/SWA/PVC,etc), derating values are publish by cable manufacturers and are based depending on their area (IEC, NEC, etc) and I...

Being close to the submain setting doesnt really matter to the fault currents. And you'll never know when and where the fault will occur. Besides as what you have said discrimination is required at all levels. Dont go for an irrational explanation. Consult your CB manufacturer for various...

For cable resistance and reactance your temp to be considered is 90C., its permissible operating temp. Your assume temp should be 20C. You also have to look for the short circuit carrying capacity of your cable. Hope this helps.