Kva

[cowboy]

Have been asked to complete and explain an installation certificate for coursework. What is Kva? How is it measured and what is the typical value for a single phase dwelling?

 

[ban-all-sheds]

Shouldn't you be asking your lecturer this?

kVA: Multiply Volts by Amps and divide by 1000.

Maximum demand for a dwelling?

I dunno - you could do this:

Lighting

10 tungsten light points at 100W each 1000W

Total 1000W

Applied diversity at 66% of total 0.66 x 1000 = 666W

Assumed current demand for lighting 666/230=2.9A

Power

2 ring circuits at 32A
=1 at 32A
+1 at 40% 0.4 x 32 = 12.8A
1 radial circuit 20A x 40%= 8A
1 immersion heater at 3kW =3000/230=13A
1 10.5kW showers 10500/230 =45.65A
1 cooker rated at say 6.5kW plus a 13A socket in controller 6500/230=28.26A
applied diversity = 10 +30% x 18.26 +5=20.47A

Assumed current demand for power =131.92A
Maximum Demand
Total assumed max current demand 2.9 + 131.92=134.82A

But the trouble is that if you do that, you always get an answer which is too big for a single phase supply. And as I don't think that people are popping their service fuses all the time, I don't think that those applied diversity rules are right...

 

[IanDB]

kVA: Multiply Volts by Amps and divide by 1000.

No, not quite, VA is Volts x Amps x Power Factor. Volts x Amps is Watts.

On a normal domestic dwelling you would expect the Power Factor to be close to 1 as most heavy loads are resistive i.e. lighting, cooker, heating.

To measure kVA you have to know the current, voltage and power factor.

I've never heard of it ever being done on a domestic installation - must be a trick question

 

[GrantD]

You've got it the wrong way round.

Volts x Amps = Voltamps = apparent power
(ignores phase angle, power factor)

Volts x Amps x Power Factor = true power
(allows for phase angle)

 

[GrantD]

Should have said

Volts x Amps x Power Factor = Watts = True power

 

[IanDB]

You've got it the wrong way round.

Brain dropped out of gear, must be having a bad day! It must be age.

 

[GrantD]

Happens to most of us sometime

 

[AdamW]

You're all wrong,

kVA = kungliga vetenskapsakademien (the Swedish Royal Academy of Science)

 

[GrantD]

or ...

Die Kreislauf- und Verwertungsagentur eG (KVA) ist ein Netzwerk von Wirtschaftspartnern, deren gemeinsames Ziel die Nutzung von Marktchancen und ...
www.kva.de/


::::::::::::::: 안녕하세요 대한배구협회입니다 ...국내외 배구대회및 슈퍼리그 정보, 비치 발리, 경기규칙, 위반, 심판, 핸드시그 .
www.kva.or.kr/


Kva! Kvak!Kva! Kvak! Esperantaj ... Prezento [Pri kio temas?] La plej freŝaj informoj! [Ĉiam legu la unua!] La plej aktuala Kva! Kvak! [

 

[securespark]

No, no, no ,no NO!!!!!!!

KVA is a theatrical lightning effects co.y

 

[pipme]

Nah, Tis Kilmerstone Village Association.

Got some mowing done today, til lunch, a few ciders, couldn't find the field afterwards, so had a few more, hey ho! It's all go !!

Don't be Co.y Sparkoda !!

P

 

[AdamW]

a few ciders, couldn't find the field afterwards, so had a few more

Don't tell oi, tell ee!

 

[securespark]

Oooh, all you lovely south western folk. Gurt lush, lover!

 

[pipme]

SS, that was S.Gloucestershire !! better one "A new modor zee, ar kid" in reference to ones 'fresh' car (probably stolen).

P

 

[securespark]

When I was working in Bristol in 1997, everyone said "Gurt lush". Thought it was pandemic...