# Diversity question



## matt1124 (Aug 23, 2011)

I’d never make it as a UK spark because none of this makes sense to me. Did autocorrect do you wrong here, sir?


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## Majewski (Jan 8, 2016)

Lbond007 said:


> Can someone clarify for me whether you apply diversity before or after working out In? Because at my college we always work out In from Ib but surely if you apply diversity after fable selection you would potentially have to use a lower rated circuit breaker??


call an electrician


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## Lbond007 (12 mo ago)

Majewski said:


> call an electrician


Cheers mate really helpful 👍


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## Majewski (Jan 8, 2016)

Lbond007 said:


> Cheers mate really helpful 👍


ya well or disregard the forum rules and just do what u want.


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## MikeFL (Apr 16, 2016)

@gpop can you translate please?


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## Majewski (Jan 8, 2016)

MikeFL said:


> @gpop can you translate please?


hes not a sparky


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## Majewski (Jan 8, 2016)

MikeFL said:


> @gpop can you translate please?


do u need gpop to type it instead? lol


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## gpop (May 14, 2018)

well its simple

In the context of electricity, the diversity factor is *the ratio of the sum of the individual non-coincident maximum loads of various subdivisions of the system to the maximum demand of the complete system*. is time dependent as well as being dependent upon equipment characteristics. 

Of course i have no f-ing idea what that mean other than hes a engineering student so hes talking bollocks like a engineer.


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## joe-nwt (Mar 28, 2019)

gpop said:


> In the context of electricity, the diversity factor is *the ratio of the sum of the individual non-coincident maximum loads of various subdivisions of the system to the maximum demand of the complete system*. is time dependent as well as being dependent upon equipment characteristics.


Everyone knows that. 

'Cept Boris.


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## Almost Retired (Sep 14, 2021)

gpop said:


> well its simple
> 
> In the context of electricity, the diversity factor is *the ratio of the sum of the individual non-coincident maximum loads of various subdivisions of the system to the maximum demand of the complete system*. is time dependent as well as being dependent upon equipment characteristics.
> 
> Of course i have no f-ing idea what that mean other than hes a engineering student so hes talking bollocks like a engineer.


could that be the simple calculation of load for sizing a building service?
Im assuming that "In" is current and "Ib" hopefully is voltage

otherwise as Gpop said "Of course i have no f-ing idea what that mean other than hes a engineering student so hes talking bollocks like a engineer. "


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## gpop (May 14, 2018)

Almost Retired said:


> could that be the simple calculation of load for sizing a building service?
> Im assuming that "In" is current and "Ib" hopefully is voltage
> 
> otherwise as Gpop said "Of course i have no f-ing idea what that mean other than hes a engineering student so hes talking bollocks like a engineer. "


depends is fable was meant to be table.


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## Lbond007 (12 mo ago)

matt1124 said:


> I’d never make it as a UK spark because none of this makes sense to me. Did autocorrect do you wrong here, sir?
> [/QUOTE
> Gue





Almost Retired said:


> could that be the simple calculation of load for sizing a building service?
> Im assuming that "In" is current and "Ib" hopefully is voltage
> 
> otherwise as Gpop said "Of course i have no f-ing idea what that mean other than hes a engineering student so hes talking bollocks like a engineer. "
> I'm not an engineering student,


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## Almost Retired (Sep 14, 2021)

what say you @Lbond007 ??


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## Lbond007 (12 mo ago)

I'm not an engineering student. In the UK Ib is design current (I.e the max demand) and In is the nominal rating of the circuit breaker you work out from your design current (e.g. if the design current (Ib) is 29 amps then the circuit breaker you would use would be rated at 32 amps (In)) And meant to put cable not fable


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## gpop (May 14, 2018)

Ib by the way is design current

so lets flesh this out
Can someone clarify for me

is it correct to apply* non-coincident loads* before or after working out current setting of a protective device? Because at my college we always work out current setting of a protective device from design current but surely if you apply *non-coincident loads* after table cable selection you might have to use a lower rated circuit breaker??

edited after a stern talking to....lol i like this guy but hes a engineer i can smell it


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## Dennis Alwon (May 9, 2009)

I think perhaps he is talking about diversity meaning de-rating. Sorry for our ignorance but we truly don't understand the question.


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## Lbond007 (12 mo ago)

gpop said:


> Ib by the way is design current
> 
> so lets flesh this out
> Can someone clarify for me
> ...


I'm really not an engineer lol I'm a second year electrical installation student. Also I dont know what non coincident loads are.


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## Lbond007 (12 mo ago)

I think a UK electrician is who I need to speak to. Thanks for trying to help tho.


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## Almost Retired (Sep 14, 2021)

Lbond007 said:


> I think a UK electrician is who I need to speak to. Thanks for trying to help tho.


you are correct !!!!!


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## matt1124 (Aug 23, 2011)

If you’ve already selected a cable, then apply more load to it than it can handle, then yes, you would have to use a smaller breaker than you need… but I don’t think that’s what you’re asking in total, I think what we’re scratching at is a feeder calculation and the over current protection of that feeder. Just my guess.


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## Lbond007 (12 mo ago)

Almost Retired said:


> you are correct !!!!!


I posted my question to UK electrical forum, its not unreasonable for me to assume that British electricians would be on here


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## Majewski (Jan 8, 2016)

Ib ≤ In ≤ Iz


Ib would be what your load is (motor or whatever) it means “design current”
In is breaker size 
Iz would be wire size

For the dummys. Goto





TLC Electrical Supplies


TLC Electrical Supplies - fast online sales of electrical cable, wiring accessories, lighting, heating and security equipment



www.tlc-direct.co.uk


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## Majewski (Jan 8, 2016)

Lbond007 said:


> I posted my question to UK electrical forum, its not unreasonable for me to assume that British electricians would be on here


Not at all but the idiots all chime in anyways plus ur not a sparky


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## Lbond007 (12 mo ago)

Majewski said:


> Not at all but the idiots all chime in anyways plus ur not a sparky


Fair enough, never been on these forums befor


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## Lbond007 (12 mo ago)

matt1124 said:


> If you’ve already selected a cable, then apply more load to it than it can handle, then yes, you would have to use a smaller breaker than you need… but I don’t think that’s what you’re asking in total, I think what we’re scratching at is a feeder calculation and the over current protection of that feeder. Just my guess.


A lot of the terminology youre using is alien to me so it's hard for me to understand, but again, thanks for trying to help


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## Majewski (Jan 8, 2016)

Lbond007 said:


> Fair enough, never been on these forums befor


well its PRETTY COMMON that each bbs has a set of rules, u seemed to blow by those lol


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## gpop (May 14, 2018)

Lbond007 said:


> I'm really not an engineer lol I'm a second year electrical installation student. Also I dont know what non coincident loads are.


Loads that would not be expected to be used at the same time. Its a bit like the starting current of a motor only the largest motor has to be taken into account and only once as you would not expect to start all the motors at the same time. Its also why they mention time and characteristics.


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## Slay301 (Apr 23, 2018)

Lbond007 said:


> Cheers mate really helpful 👍


People love u today


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## gpop (May 14, 2018)

I think the college is correct. 

Breaker protects the wire. Wire has to be rated for full load where the breaker can be rated for expected load.


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## matt1124 (Aug 23, 2011)

Slay301 said:


> People love u today


vote Majewski for moderator 🗳 🗳


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## MikeFL (Apr 16, 2016)

Lbond007 said:


> I think a UK electrician is who I need to speak to. Thanks for trying to help tho.


@gpop is our resident British Electrician. 
We stole him from you a few years ago and today we hide him in the Florida Everglades.

Certainly an interesting thread.


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## Majewski (Jan 8, 2016)

matt1124 said:


> vote Majewski for moderator 🗳 🗳


i literally have helped and answered all the uk chit for days but please, lets keep disregarding the actual help.


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## Lbond007 (12 mo ago)

Lbond007 said:


> A lot of the terminology youre using is alien to me so it's hard for me to understand, but again, thanks for trying to help


What does "feeder calculation"


gpop said:


> Loads that would not be expected to be used at the same time. Its a bit like the starting current of a motor only the largest motor has to be taken into account and only once as you would not expect to start all the motors at the same time. Its also why they mention time and characteristics.


Okay that makes more sense. That is basically what I mean by diversity (I think). Design current is the current on full load. In a lighting circuit in the downstairs of a house for example it is unlikely that that circuit will be on full load because most of the time not all of the lights will be switched on at the same time. When you allow for diversity you take this into account and it means you can use a lower rated circuit breaker and thus smaller cables.


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## Lbond007 (12 mo ago)

Lbond007 said:


> What does "feeder calculation"
> Okay that makes more sense. That is basically what I mean by diversity (I think). Design current is the current on full load. In a lighting circuit in the downstairs of a house for example it is unlikely that that circuit will be on full load because most of the time not all of the lights will be switched on at the same time. When you allow for diversity you take this into account and it means you can use a lower rated circuit breaker and thus smaller cables.


For example in a domestic dwelling (a house) a the diversity allowance for a lighting circuit is 66% of the design current


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## Lbond007 (12 mo ago)

gpop said:


> I think the college is correct.
> 
> Breaker protects the wire. Wire has to be rated for full load where the breaker can be rated for expected load.


That was all I needed haha. Thanks


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## gpop (May 14, 2018)

MikeFL said:


> @gpop is our resident British Electrician.
> We stole him from you a few years ago and today we hide him in the Florida Everglades.
> 
> Certainly an interesting thread.



lol im 20 years out of date that's like a knob and tube guy answering a gfci question.


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## Wardenclyffe (Jan 11, 2019)

Lbond007 said:


> I'm really not an engineer lol I'm a second year electrical installation student. Also I dont know what non coincident loads are.


Noncoincident loads are *two or more loads that are unlikely to be in use simultaneously*, so only the larger of the two loads must be used for the calculation. Careful use of this optional calculation can save customers money and still provide a very safe and effective job. 


Google time,...


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## kb1jb1 (Nov 11, 2017)

I thought the OP was inquiring about hiring practices. One white, one black, one Asian, one female, one LGBTQRST, etc...


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## Majewski (Jan 8, 2016)

kb1jb1 said:


> I thought the OP was inquiring about hiring practices. One white, one black, one Asian, one female, one LGBTQRST, etc...


clearly


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## matt1124 (Aug 23, 2011)

kb1jb1 said:


> I thought the OP was inquiring about hiring practices. One white, one black, one Asian, one female, one LGBTQRST, etc...


One black, one white, one red, and one white with red stripes, and one bare 😈


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## mburtis (Sep 1, 2018)

Why do we even have a UK forum section, every time a question is posted nobody understands it so just responds like jackasses and runs the guy off. This place has really went down hill the last several weeks.


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## Majewski (Jan 8, 2016)

mburtis said:


> Why do we even have a UK forum section, every time a question is posted nobody understands it so just responds like jackasses and runs the guy off. This place has really went down hill the last several weeks.


My answer was legit lol. Go cry in your room


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## LGLS (Nov 10, 2007)

gpop said:


> well its simple
> 
> In the context of electricity, the diversity factor is *the ratio of the sum of the individual non-coincident maximum loads of various subdivisions of the system to the maximum demand of the complete system*. is time dependent as well as being dependent upon equipment characteristics.
> 
> Of course i have no f-ing idea what that mean other than hes a engineering student so hes talking bollocks like a engineer.


Not really bollocks. It's like when the 12 baseboard and unit heaters in my home calculate to 60K watts... but they'll never all come on simultaneously. Except when they do.


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## LGLS (Nov 10, 2007)

mburtis said:


> Why do we even have a UK forum section, every time a question is posted nobody understands it so just responds like jackasses and runs the guy off. This place has really went down hill the last several weeks.


Don't worry, I'm back and I'll straighten out some of these arses...


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## Majewski (Jan 8, 2016)

LGLS said:


> Don't worry, I'm back and I'll straighten out some of these arses...


thank goodness


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## GladMech (Sep 18, 2020)

Don't be doing any of that 60% nonsense for lighting in MY house. I have an "all on" button. You should have seen it before LEDs! It's not bad now, but I don't have to squint anywhere!
BTW, I still have difficulty not thinking he was talking about inches and pounds. (In & Ib)


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