Really old memshield 3 phase board. New install.

[cateringENGINEE]

Hi
I have a 3 phase cooker range to install on unbalanced loads 47a / 9a / 9a.
Apparently.... I need to confirm that..
it needs a new supply that is rcd protected.
My problem is the board that it is coming from is a old memshield board 3 phase with all individual bs88 fuse carriers and no main switch isolator.
ive not come across one of these before. Usually it's a new mcb in the board and job done.
looking on the fuse carriers they mostly say 30a which I'm thinking I can't put a 50a fuse in them so would I need a new carrier?
my original idea was to put an ad box mounted to the side of the board and bring tails from the 3 phases neutral and earth through to a 3 phase rcd/mcb set up.

50a bs88 fuses - rcd - mcb - rotary isolator - appliance

i have pictures of the board and fuse carrier but don't know how to put the pics on here..?

any help or guidance would be appreciated.

thanks

 

[D Skelton]

D SKELTON do you have any electrical knowledge because you put about 10 posts on here and not one of them have shown any electrical experience? are you a 5 week wonder as well?

Ah crap! You got me!

 

[Anthony S]

I don't want to get involved, but Iv'e seen cookers/oven with odd/out of balance ratings over 3 phases.

Was verified with a clamp tester as well.

 

[davesparks]

not all three phase appliances are balanced loads. you cant just say oh 63a total that means 21a per phase.
if you got 8 elements 2 running at different wattages to the other 6 split over 3 phases it wont work out equal.

How much work have you done with 3 phase loads? I'm guessing not a lot! If a 3ph appliance is quoted as requiring a 32A supply for example it needs a 32A 3 ph supply. NOT a total of 32A if you add all the phases up.

No an appliance won't always be balanced but the manufacturer will have taken this in to account when writing the spec for the supply it needs.

Spec'ing a 3ph supply by how many amps each phase needs is in the least a very daft idea!

 

[davesparks]

Ah crap! You got me!

You're secrets out!

 

[shanky887614]

i dont even know why this thread exists.

in 3 steps

1. check appliance for brand
2. check for model on sticker/unit
3. go on there website or call them and they will tell you what is the minimum supply it needs.

why is this so difficult it takes minutes

 

[D Skelton]

i dont even know why this thread exists.

in 3 steps

1. check appliance for brand
2. check for model on sticker/unit
3. go on there website or call them and they will tell you what is the minimum supply it needs.

why is this so difficult it takes minutes

IN ONE STEP!

Get a qualified electrician to do the work!

How many times?!

 

[ipf]

Ah crap! You got me!

:dunce2: say ne more..

 

[Anthony S]

i dont even know why this thread exists.

in 3 steps

1. check appliance for brand
2. check for model on sticker/unit
3. go on there website or call them and they will tell you what is the minimum supply it needs.

why is this so difficult it takes minutes

That's the one

 

[cateringENGINEE]

How much work have you done with 3 phase loads? I'm guessing not a lot! If a 3ph appliance is quoted as requiring a 32A supply for example it needs a 32A 3 ph supply. NOT a total of 32A if you add all the phases up.

No an appliance won't always be balanced but the manufacturer will have taken this in to account when writing the spec for the supply it needs.

Spec'ing a 3ph supply by how many amps each phase needs is in the least a very daft idea!

we've established its 3 phase and also established its total load is 63a.. where did i say it needs to be on a 63a supply because thats what all the phases add up to?
i didnt, i said ive been given this load information which doest look quite right but ill find out monday, but just because it is total load is 63a does not necessarily mean its 21a per phase which some people didnt get but #32 clarified what i was trying to get across.
there will be a data plate on the back which will explain all and also prove the info i got given isnt quite right. so until then its irrelevant, i needed to know about the board mainly which i wasnt familiar with which i got on #26.
the rest i can deal with when i get there..
thanks for the answers, its been amusing.
D Skelton no hard feelings, its all banter. but if you not going to answer any questions then its a waste of time typing.

 

[cateringENGINEE]

That's the one

becasue it was originally about the pictures on page 1

 

[TJ Anderson]

we've established its 3 phase and also established its total load is 63a.. where did i say it needs to be on a 63a supply because thats what all the phases add up to?
i didnt, i said ive been given this load information which doest look quite right but ill find out monday, but just because it is total load is 63a does not necessarily mean its 21a per phase which some people didnt get but #32 clarified what i was trying to get across.
there will be a data plate on the back which will explain all and also prove the info i got given isnt quite right. so until then its irrelevant, i needed to know about the board mainly which i wasnt familiar with which i got on #26.
the rest i can deal with when i get there..
thanks for the answers, its been amusing.
D Skelton no hard feelings, its all banter. but if you not going to answer any questions then its a waste of time typing.

Definitely speak to the manufacturer on this one. There is also load diversity that you can apply to this. See what they suggest for the supply. Once you have ascertained this, take existing phase loadings into account when connecting your unbalanced load to balance it out the best you can.

 

[Anthony S]

becasue it was originally about the pictures on page 1

I'm sure your be fine once you find out the loading across each phase.