Receptacle load for European Load Calc

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mic

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Hey all,

We are building a portable office for a European client and I need to do a load calc for feeder size and power requirements. I have not been able to figure out the standard load of a general purpose 16A (240V) receptacle. IEC 60364-7-717 and 60364-5-54 have not been overly helpful.

Also, I have been assuming that if we have a known load on a receptacle then we can use that value in the load calc.

Any insight would be appreciated.

Mic
 
I recall a project over in Euro-land where the installation was required to comply with certain national requirements. When we finally got an English version copy, we discovered it was similar in scope to our beloved NEC. I recommend contacting your European customer, explain to them what you are trying to determine, and asking them to help locate an English version of their national electrical codes. It may contain the information you require.

As an alternative, you could also use the NEC procedures, prepare a 'letter of intent' describing what you are doing, and get it to your customer for approval.
 
Thanks,

The IEC standards were quoted as the electrical code. Unfortunately they are very vague. There was reference to a 30A (240V) circuit could not supply an area larger than 1000 sqr ft. I didn't find anything that corresponded to a base load on a general purpose receptacle. In about 70% of the cases I know the actual load but the other 30% are a mistery.

In the past, I used 180VA for a 15A, 120V receptacle (based on the NEC). I was hoping to find a quick easy number like that for the 16A, 240V European receptacles. Let me know if I am asking for the moon.

Mic
 
mic said:
In the past, I used 180VA for a 15A, 120V receptacle (based on the NEC). I was hoping to find a quick easy number like that for the 16A, 240V European receptacles. Let me know if I am asking for the moon.
Click to expand...

I believe you are.

I used to live in the UK, and have more than a passing familiarity with the UK wiring regs. There is not a number you can assume per outlet, you need to apply diversity calculations over the installation. There are rules governing how the diversity is calculated. Not got the UK regs in front of me at the moment, so can't be more specific.

What country are you speccing for...?
 
The offices are not designed for a specific country but can be deployed throughout the EU. We are allowed to use the British standards (BS7671) but I couldn't find details on load calculations, but I may be looking at the wrong standard.

Otherwise we must abide by the IEC, which seems to let you do anything you want to as long as you test and document it.

I usually try to avoid being creative in my numbers, but in this case I may have to.

Thanks.

Mic
 
I used to do design with BS standard and IEC standard long time ago. I am pretty sure both standards have the receptacle loads for electrical load calculation. But I couldn't remember which article is about that.
 
BS7671 is the right standard, it's the IEE wiring regs.

There is no magic number like 180W that you can use, sorry, section 311-01-01 applies, which says "The maximum demand of an installation ... shall be assessed. In determining the maximum demand ... diversity may be taken into account"

Now in the previous edition of the wiring code there was Appendix 4, entitled "maximum demand and diversity", which gave rules of thumb for calculating maximum load. That is no longer present in the 16th, you are responsible for working it out yourself. This is the general trend in UK regs, the installer is becoming more responsible for selecting the correct arrangements. It's exactly opposite to the NEC and to this very forum. On this forum the debate is always about which exact parts of the NEC apply to some particular situation, but the exact answer is always somewhere in the NEC. A similar UK based forum would disagree simply over how to do stuff, with there being no one right answer.

Anyway, for a portable office, the only things that you probably have is lighting (take 90% of full load), heating (take 100% of largest heater and 90% of the rest), take 100% of water heater.

Sockets are a tad harder, as the UK 13A sockets are assumed as the norm, and you note you're using 16A sockets. For non-13A sockets, the rules go 100% of largest point of utilisation and 75% of the current demand at every other point of utilisation. I assume (but don't know) that in this context a point of utilisation is a socket. It's an undefined term.

Hope that helps. But remeber these are the old regs, you need to make your own assessment.
 
Thanks, that does help a lot. Not quite the answer I was hoping for, but at least I can move forward.

Mic
 
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