Electrical Load or Amps

[domapegitashi]

I have a small building to design. The main supply is from another building (existing) which is 3 phase and 63A protection (not sure about it). It is 7 way and 3 are spare. L1 is 96A, L2 is 54A and L3 is 84A. I am looking forward to use L2. But the new building have a load of 82.1A and probably require 100A protection. I think L2 is not big enough for the new one. Can some one fire any idea weather to get a new 3 phase line or use one of 3 spare and distribute the load across. Can existing building (3 phase 63 A) enough to take this new load?

Any one have any thought about it?

 

[Knobhead]

Designing a building, think you’ve got the wrong forum. Try architects third door down the corridor on the left.

 

[Darkwood]

Would help if we new the size of the supply at the origin ... quoting numbers means nothing if we cant relate them to the size of the incoming supply????

Also can you elaborate on your electrical design, show calcs etc as we would be giving misguided advice if the values you give are incorrectly worked out and could end up with wasted costs or over-demand.

@Tony ... you sure 3rd door i thought it was the 5th?

 

[Knobhead]

No the 5[SUP]th[/SUP] door is the alzheimer's forum. It could be the next room but I can’t remember.

 

[ezzzekiel]

for gods sake will they all stop moving offices, cant seem to find anyone these days,

and yes i have a thought about it, infact i have a few but could do with more imformation.

 

[Darkwood]

No the 5[SUP]th[/SUP] door is the alzheimer's forum. It could be the next room but I can’t remember.

I know door No4 is for people with short atten........ ooh Ice-cream van!:wacko:

 

[domapegitashi]

Guys thanks for quick reply. Really appreciated that.

Well for the new build for lighting load (2.5W) is 17.76 Amp, Instantaneous heater (3kw) - 13.04 Amp, Hand dryer (1.5W) - 6.52A, Electric heater (1500w eachx3) - 14.78A and ring main 32A which gives 82.1A (round up 100A max demand) in total. The existing one has 8 way 3 phase DB. Consist of 1. (R-16A, Y-16A & B-6A), 2. (R-32A, Y-16A & B-6A), 3. (R-16A, Y-6A & B-16A), 4. (Spare), 5. (R-16A, Y- spare (where it was initially proposed to supply the new build, but now it is not possible as new current demand is 82.1A & B- 40A), 6. (Spare), 7. (R-Y-B- 16A each) and 8 & 9 are both spare. The main supply is probably from feeder pillar (Merlin Gerin Type 630 - BS BSEN 60947 IE 630A). The size of the cable is 4 core 35mm2 to existing building (400V 63A Isolator). The one with bold, I am not sure about it cause I was verbally mentioned by 3rd person.

The size of the building is 99mm2. It has i think 10 double socket out. Is 32 Amp MCB is enough to protect it?

Hopefully I can get rigid information in few days time.

I have a small building to design. The main supply is from another building (existing) which is 3 phase and 63A protection (not sure about it). It is 7 way and 3 are spare. L1 is 96A, L2 is 54A and L3 is 84A. I am looking forward to use L2. But the new building have a load of 82.1A and probably require 100A protection. I think L2 is not big enough for the new one. Can some one fire any idea weather to get a new 3 phase line or use one of 3 spare and distribute the load across. Can existing building (3 phase 63 A) enough to take this new load?

Any one have any thought about it?

i tried to switch to the architecture one but I failed it. Spent 30 min on it still not succesful.


​

 

[Darkwood]

I afraid you totally lost me your missing fundemental basics in electrical design when weighing up current demand of an installation your clearly out of your depth here and this should be undertaken by a competent Electrician who has installation design experience, your values re confusing and the size of the building nearly made me spill my beer.... i mean 99mm2 is going to make a wendy house look like a castle.
I hope you realise with exception of my humour im trying to give you a reality check here im not sure of your background or qualifications but the way you are gauging your demand is totally incorrect and should be basic knowledge to you if you are undertaking this kind of project.

 

[electric will]

lighting load (2.5W) is 17.76 Amp,

 

[electric will]

2500 watt at 230 ain't even near 17 odd amp is it? Well hope not anyway, not got my maths head on tonight

 

[Darkwood]

2500 watt at 230 ain't even near 17 odd amp is it? Well hope not anyway, not got my maths head on tonight

I assume its mainly low or high bay inductive fittings thus a 1.8 factor but as this comes to 19amps i assume its not all inductive thus where he has arrived at 17amps.

 

[electric will]

2500 watts at 230 volts is 10.86 amp, isn't it?

- - - Updated - - -

Please say yes

 

[Darkwood]

2500 watts at 230 volts is 10.86 amp, isn't it?

- - - Updated - - -

Please say yes

This would be correct for resistive lighting but as i said from the answer hes given it sounds like a large percentage of it is inductive thus will require extra calc (x1.8) and this gives 19.6 which is greater than his result..... this is why i assume not all the lighting is inductive but without a breakdown its an educated guess.

 

[Rockingit]

I think our OP may not be from these shores, gents.

 

[domapegitashi]

lighting load it is 2.5kw = 0.9 x 2500 x 1.8
---------------- = 17.76A (lighting includes flourscent light, security flood light and emergency)
230

floor area = 18500 x 5400 = 99.9 m2 (single 32A ring circuit may serve a floor area up to 100m2)

 

[Hiddo]

lighting load it is 2.5kw = 0.9 x 2500 x 1.8
---------------- = 17.76A (lighting includes flourscent light, security flood light and emergency)
230

floor area = 18500 x 5400 = 99.9 m2 (single 32A ring circuit may serve a floor area up to 100m2)

Where is the 0.9 from?

Why would you want to design and install a RFC that is very nearly at its maximum from day one?

Wouldn't you want to install two RFC's to cover for any future growth or requirements?

 

[domapegitashi]

Where is the 0.9 from?

Why would you want to design and install a RFC that is very nearly at its maximum from day one?

Wouldn't you want to install two RFC's to cover for any future growth or requirements?

RFC what are they???

 

[domapegitashi]

ring final circuit. thinking too adding extra but would it not increase the total I demand from 82.1 A to over 100A.

 

[Hiddo]

Forget it!! You clearly have no idea what you are talking about. Please get a competent person (electrician) in before you either:

A - Kill yourself

B - Kill Someone Else

C - Burn The Building Down

D - All of the above.

 

[Guest111]

Is this a wind up?

 

[Brightspark2]

Instead of installing a 32A ring final which will take you over your 100A limit install a 16A radial which would you keep you under the limit...then because your using half the current of the ring final you can install twice as many...

Easy...

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