When relating to engineers I hear this quote: "Engineers should be on tap, not on top". What does this mean?

Question

I've read it hear and there and one or two people may have mentioned around the engineering department, but nobody seems to know where the quote came from.

Answer 1

The expression means that the services of engineers should be available, but the engineers should not be in charge.   "On tap" means available, like water is available from a tap (that is, from a faucet).   "On top" means in charge -that is, being the boss.

Its origin appears to be unknown.  The saying isn't peculiar to engineers, but has also been applied to various other categories of people.   For example  .....

the following website makes use of the expression, "Professionals should be on tap, not on top," with reference to health professionals in the UK, and generally with the same meaning (available but not in charge) as for the engineers.

     http://jech.bmj.com/cgi/content/extract/...

In addition, the following website uses "Indian Art on tap but not on top" with a meaning I do not find clear. (I didn't read the article carefully, but think it means on top of the art market in terms of selling prices):

   http://mokshaart.blogspot.com/2006/01/in...

The following site refers to an article entitled, "Solid-State Experimentalists: Theory Should be on Tap, Not on Top":

http://adsabs.harvard.edu/abs/1990PhT......

And the following site discusses the principle of  "experts on tap, not on top" with respect to community planning, & with the idea that the citizens may do a better job of planning some things than the experts.

http://www.designingforcivilsociety.org/...

Evidently the phrase, "on tap, not on top" has become a buzz phrase or cliche, like "the bottom line" and "at the end of the day," and you've heard someone applying it to engineers in some context.   It could be said about any group that a person thinks would be useful, but that shouldn't be in charge of something.  

You can find additional uses of "on tap but not on top" at the following link, which shows Google lists about 1,500 references to it:

http://www.google.com/search?hl=en&q=%22...