***Cont../ Useful Information for Electricians & Apprentices***

[amberleaf]

O.S.G.. The use of other methods’ of determining Maximum Demand is Not Precludedwhere Specified by the Installation Designer

FirstlyI make no Apologies for the Way am Writing on any Matters . it can be a first day Apprentice or some one Needing aJog of Memory .
Sowe are all in the Same Boat . “ To Learn “

For the Apprentices . The Day we stop learning is the Day we hang Upour Tool-Bag

CookerDesign Current Calculations

Thefirst thing you have to do is get Your Head around the Calculations !!

(From a Design point of View ) 2392-10

DomesticInstallation Oven(s) & Hob(s) are to be Calculated upon their MAXIMUM LOADING
Startwith a simple Calculation ( An Oven has a rating of 2kW ) 2000

(I = P/V ) Formula … I = 2000 ÷ 230V = 8.70A …. Weare Using the Unit Amps


2392-10/ Domestic Installation Oven(s)

Ovenhas 4 Rings ( 2 x 1kW ) & ( 2 x 1.5kW ) & Grill ( 2kW ) & Oven (3kW )

-Controlled via a CookerSwitch with a Socket outlet .

Asa Designer . we’ll have to Apply Diversity ??

Important )- Diversity allowance to be Applied to the FULL LOAD CURRENT for CookingAppliances .

TheO.S.G. is telling us . Purpose of the Final Circuit fed from theConductors )
O.S.G.Table 1B p/97 – column (3) Cooking Appliances → At the Top of the Page Note : Type ofPremises ( 2392-10 → Household Installations ) Domestic Installation(s)

DomesticInstallation(s) Only O.S.G. - 10A + 30% f.l – Full Load ) of connected Cooking Appliances in the Excess of 10A+ 5A if a socket-outlet is incorporated in the Control Unit . ( C.C.U. ) – 45A + 13A Socket Switched with Neon .

Fromyour point of View ( The First 10A ofthe rated current plus 30% of the reminder ( Plus) 5A if the Control Unit incorporates s Socket.

Calculations)- You bank “ Hold OFF“ the first 10 Amps of the Maximum Load Current )
The10A will be used at the End of the Calculations’

-So your Work out the Total Power Rating & then calculate the Full Load Current

Calculations)- Power = ( 2 x 1 ) + ( 2 x 1.5 ) + ( 2+ 3 ) = 10kW

I= 10000 ÷ 230V = 43.48A … round it up to the first four numbers43.47826087 ( 48 ) 43.48A

UsingDiversity allowance stated ↑↑ ( 43.48A sub 10A = 33.48A )

I= 33.48 x 30 ÷ 100 = 10.04A

Youradding the ( 5A ) for Socket outlet . I = 10A + 10.04 + 5A = 25.04A )- Asa Designer this is your Expected Current Demand .

Remember )- Supply Cables Rated to suit DesignCurrent ( Iz )

 

[amberleaf]

Purposeof . Periodic Inspection & Testing . 621.2. is to provide an Engineering view . on whether or not theinstallation is in a satisfactory condition where it can continue to be usedSafety .

Itshould be noted that the initial . sample size is only based on a . walk-round .& consultation of . records . further . that what may at first appear to begood . E.g. the quality of maintenance . may turn out to be poor during the detailed inspection & testing .

Suggestedprocedure for setting . Initial & adjusted sample size .

Conductinitial “ Walk round “ survey &establish initial sample size .
▼
Carryout Inspection & Testing . based on initial sample size .

▼ Good results .
Goto final report .

▼ Intermediate/ poor results .
Increasesample size . or discuss with Client . whether further investigation is required .

 

[amberleaf]

Stillthe same . 2391-10 :

Low-résistanceohmmeters . BS-EN-61557-4 .
(IR ) testers . BS-EN-61557-2 .

Earthfault loop impedance testers . BS-EN-61557-3 .
Thismeans that the instrument should cut OFF the test current after [ 40mS ] Etc .

(RCD ) testers . BS-EN-61557-6 .
Reminder . 2392-10 . -&-s
Tocheck RCD . operation & to minimise danger during the “ Test “ the test current should be appliedfor no longer than [ 2s ]

Phaserotation instruments . BS-EN-61557-7 .
Exams: Mechanical . visual & / or audiblemeans .

 

[Dan]

I'm just bumping some of the older threads in the general electrical forum that had a lot of replies. They might not be current topics, if they're not, just ignore them and they'll soon drop off the list. If you DO wish to add a reply and get the conversation going again, feel free to do so. Your input might help somebody else in the future.

 

[Dan]

I'm just bumping some threads in the Electrical Forum, don't mind me while I do this, you don't have to respond to them. Although if they are still current topics, and you do wish to reply, you're welcome to. Keep the thread on-topic and make sure you stick to the forum rules though.