Drawout Type MCCB

"How can i justify it to my client?"

By having proper documentation and back-up information given to you by a qualified engineer who is familiar with the project requirements.

I'd also ask them to represent you with the customer, who will see immediately that you don't have a clue, if you try to bluff your way through this using total strangers as your only reference.

Hire an engineer.

By the way. Why didn't you give the customer what they wanted in the first place?????

Now you're trying to justify your companies incompetence with smoke and mirrors.

Actually our client had ordered us to make panel with drawout type MCCBs & we made it with fixed type MCCBs. How can i justify it to my client?

You mean how can you get out of your mistake.

Supply the customer with what they specified, ordered AND paid for free of charge (at your expense). The customer is right in this case and likely had very good reasons for ordering the panel with drawout type MCCCB(s).

Additionally talk it over with your customer - if you have made a mistake TELL them that and see what the two of you can work out, perhaps the two of you can compromise on a solution.

Don't try and bull$hit them because if you have to ask this question on a forum then the customer probably knows more than you do and it will only make things worse.

_{Jack - The customer is always right.}

Cheaper price is the principal justification. But if it was cheaper only to you, and not to the client, that would be very poor justification.

Wow, gotta love the size of his big brass cojones...

Can you imagine?

"I was low bidder on this drawbridge, but decided to build it as a fixed bridge. Please can someone tell me the advantages of a fixed bridge over a drawbridge so that I may explain to my customer why he does not need a drawbridge."

That's an interesting parallel.

So you want to CYA? Why the h*** did you not use drawout MCCBs in the first place? OK, others have covered all this rather well (especially the bridge analogy)

You should really have convinced the customer to save himself some money at the time of ordering... "MCCBs are not maintainable, so why drawout? You can only replace an old, (perhaps damaged) MCCB with a new one. You can as well take a little time about it and save yourself the extra cost. Not to mention the extra plug contacts which will add to the heat in a drawout MCCB...." Any number of good reasons are available for both, provided you know the business, which you don't seem to know. Want me to convince you why drawout MCCBs are better?

• "MCCBs are not maintainable, so why drawout?"

So that you can remove and replace a single MCCB in a panel without killing power to the entire panel. That's the ONLY reason I have ever had to use one.

Exactly one in a 30+ year career...

But when I worked for Siemens, we offerred that accessory and I recall seeing a presentation from the product group that indicated some specific industries that required them in certain applications. Can't remember the industries or the applications now though, I just remember thinking "Oh well, I don't have any of that around here, make room for some other piece of trivia..."

Hi,

Advantages of fixed type MCCB over drawout type MCCB.

1) Fixed type MCCB's can be mounted in any orientation (vertically and horizontally).

2) Foot print of the MCCB is very less when compare to the draw out type MCCB.

3) Contact losses are more in draw out type (connection is made with spring reinforced jaw clamps designed to hug the bus in draw out type MCCB, so if spring fails then the temperature rise in the contacts points will lead fire hazardous)

4) and of course the price is cheaper.

Re: 1) and 2), The draw-out accessory for the Siemens VL series breakers I saw were not subject to any orientation constraints and were barely a fraction of an inch larger footprint than the breaker itself. The depth was significantly more, but you said footprint.

The two biggest advantages are safety and up-time.

Safety because a drawn out breaker can't be "accidentally" closed and energize a locked-out circuit, also the type of construction reduces the level of potential arc-flash exposure and the required type of PPE.

Up-time because a draw-out breaker can be replaced in under a minute and without requiring the shutdown of adjacent circuits.

More than likely your client has a critical need to maximize the availability of power to his installation, something that you had no right to second-guess. Replace the equipment and eat the cost, you cannot justify your actions (...and maybe your client has learned to question why one bid was significantly lower than the others.)

I would love to be a fly on the wall the when you try to explain to the customer he ordered the wrong thing.

Deliver what is ordered. (don't try to justify).

And

learn from mistake....

I understand your situation. It is better to own up. Tell him you have made the wrong one and are in the process of making the right ones. Apologise to him for the error. Do not decide for the client the next time unless he allows you to do so.