Part P Doctor: 1st edition amendments…

Hi all,

Following on from lots of enquiries regarding my writing work I am pleased to announce that I am about to do a brand new 17th edition Part P Doctor book.

I have also had numerous queries about an addendum to the present work to equate the “old book” to the brand new 17th Edition.

I have now completed this and re-produce it for you below.  Now as you all can guess, I am not so good with modern technology so the lines have moved round a little.  If you would like a neater version, please do not hesitate to drop me a line at al_lynch@ntlworld.com and I shall send it back to you presently. 

Thank you again for your kind words and patience!

Alan Lynch.

 

 

The Part P Doctor Amendments

 

I would like to thank you for purchasing “The Part P Doctor” It has been a great critical success and we have been humbled with fan mail and fan club of-sorts!

Eventually there will be a new version written, but for now I would like to offer this addendum to help you equate your book to the new IEE On-site-Guide, which came on line in September 2008.

Many thanks are in order to Part P student and book purchaser Mr. Chris Daly for his help in the conception and general layout of the addendum.

Before you start with pen and correction fluid it would be useful to give the “headline” changes that have come with the new BS 7671:2008. These are:

 

• Basic protection broadly replaces “Direct contact”
• Fault protection broadly replaces “Indirect contact”
• Any circuit sunk less than 50mm into a wall without conduit around it must be 30mA rcd protected.
• All circuits of a room containing a bath or shower must be 30mA rcd protected
• All socket outlets must be 30mA rcd protected unless supplying a specific item such as a fridge. In this instance it must be marked up to tell everyone.
• Zone 3 in a bathroom is now gone.
• A socket outlet is allowed in a room containing a bath or shower as long as it is at least 3m from the tub or shower basin.
• Bathroom bonding is mostly scrapped. To explain, if everything metallic has a good earth anyway it does not need bonding.  If metal parts are fitted on plastic piping and have no earth whatsoever then those parts are not, by definition, an extraneous conductive part and so require no bonding.  The only time it would become relevant is if the resistance between accessible parts was say less than 23kW (allowing 10mA to flow through someone)- then you would have to equipotential bond.
• Most everything in a house is now on a standard 0.4 disconnection time.  The only exceptions could be say a cooker or shower above 32A which can still be 5 seconds! Another exception to 0.4s can be a sub-main to a garage or shed which can also be on a 5sec disc.
• The voltage used in calculations as well as the official declared voltage is now 230V, not 240V as before.  Hence the maximum earth loop impedances have gone down slightly.

 

The following shows you which page you should be on and what to do with amending it. As an example, look below at the line for page 30 of your book. Where the book states three times, on that particular pagep50 OSG, you simply change it to p57 OSG.

 

NOTE. All page numbers appear as “ p, XX OSG” unless stated.

 

Part P Doctor Page                        Amendment from new 17th edition OSG

 

10                                                       Replace direct and indirect with basic and fault protection

 

12                                                       Replace 6 & 89 with 5 & 100.  The bottom paragraph is now wrong as well in regard to disconnection times. Read the paragraph and then the bullet points above.

 

13                                                       Numbers at top of page should now read 0.9W & 2.10 W.  Then re-do the sums using 230 V as per final bullet point above.

16                                                       Delete last paragraph, as everything is now 230V!

 

17                                                       Replace 27-29 with 15-16 (also change the term “equipotential” to “protective” on diagram. This is to reflect the new names for these conductors)

 

24                                                       Change “Direct, indirect contact” to “Basic, fault protection

 

30                                                       Replace 50,50,50 with 57, 57, 57

 

31                                                       Replace 51,92,51, 92 with 58,103,58,103

Change loop figures from 1.20, 0.60, 0.30 to 1.16, 0.58, 0.29 W

 

32                                                       Replace 89,89,91,92 with 100, 100, 102, 103

 

33                                                       Replace 40,42 with 43, 44 (existing p4 reference is correct)

 

34-35                                                 Broadly the same scheme for reading off maximum cable lengths of circuits, just read up on section 7

 

36                                                       Replace 151,153 with 158, 159

 

37                                                       Replace 154 with 161

 

38                                                       Replace 6,85 with 5,96

 

39                                                       Replace 52,53 with 59, 60

 

44                                                       Replace 24 with 15-16

 

46                                                       Replace 28,40 with 17,134

 

 

 

47                                                       (Top paragraph) The “M6″ reference method now gone. The tables in section 7 now list new reference methods 100,101 and 102 (cables in thermal insulation in houses) The one to avoid is ref method 103 (in thermal insulated wall with cable not touching inner wall.)

                                                           (Bottom paragraph) Replace 713-07-01 with 416.2.2

 

48                                                       Replace 26,162 with 31,30

 

49                                                       Replace 155 with 161

 

(Special locations)                          This whole chapter revolved around “super-bonding” all the circuits to the metalwork in the bathroom.  This regime is effectively cancelled now with the arrival of the 30mA rcd solution.  However I will list equivalents to the new OSG.

 

51                                                       Replace 30,31 with 71,72

 

58                                                       Replace 59 with 70

 

60                                                       Replace 30-31, 59, and 30-31 with 71,70,71

           Also change reference from “asterix” to “arrow”

 

61                                                       Replace 73,92, 30 & 31 with 84, 103, 71 & 72

 

62                                                       Replace 69, 59 with 71, 70 (Note-first OSG ref is not in bold type)

 

63                                                       Replace 59 with 70

 

64                                                       Replace 129-130, 131, 132, 62, 131, 62-65 with 137-138, 139, 140, 73, 139, 73-74

 

67                                                       Replace regulation no. 514-09-01 to 514.9.1

 

69                                                       Replace 62-82 with 77-98

 

71                                                       Replace 78 with “Half way down P 86 OSG”

 

74                                                       Replace 80, 50 with 88, 57

 

75                                                       Strike out “the main fuse” and replace with “a fuse or breaker”

 

76                                                       Replace 79 with 87

 

77                                                       Replace 89 with 100

 

78                                                       Replace 129-130 with 137-138

 

79                                                       Replace 132, 40 with 140, 43

 

81                                                       Replace 69,68 with 78, 79

 

82                                                       Replace 130 with 138

 

85                                                       Replace 69 with 80

 

86                                                       Replace 70,70, 70-71 with 81, 81, 81-82

 

89                                                       Replace 132, 132 with 140, 140

 

93                                                       Replace 72, 73 with 83, 83 (Change 0.5MW reference to1.0MW)

 

97                                                       Replace 73, 73 with 84, 83 (Change 0.5MW reference to1.0MW)

 

99                                                       Replace 73 with 83 (Change 0.25MW reference

                                                           to 0.5MW)

 

102                                                     Replace 78 with 86

 

103                                                    Replace 78,78, 77, 70 with86, 86, 79, 83 (Change text of last reference from “bottom” to “top of P 83 OSG”

 

105                                                     Replace 79, 79 with 87, 87

 

106                                                     Replace 79 with 87

 

108                                                    Replace 6, 88, 92, 92 with 5, 99, 103, 103

                                                           As to the bullet point tables replace 1.20W with 1.16Ω.

Replace “Table 41B2 p46 BS7671- 1.50Ω” with Table 41.3 p49 BS 7671- 1.44Ω

 

110                                                     Replace 81 with 91

 

111                                                     Replace 131, 92, 21-22 with 139, 103, 24-25

In 4th paragraph replace 2.40Ω with the new Zs for circuit of 2.32Ω.

Also replace direct contact with “additional basic protection” and indirect contact with “fault protection” in this area

It is also worth noting that the 2nd paragraph is now voided in new regs.

 

112                                                     P60 OSG- strike out complete paragraph

 

114                                                     Replace 39 with 38

 

117                                                     Replace 6 with 5

 

118                                                     Replace 159 with 167

 

119                                                     Replace 129 with 137

 

122                                                     Replace 27-29 with 15-16

 

125-126                                             Replace the word “deviation” with  “departure” and current version of book is BS 7671: 2008

 

129                                                     Replace 140-141 with 148-150

 

132                                                     Replace 73 with 83, 84

 

133                                                     Replace 72 with 83, 84

 

135                                                     Replace 92 with 103 (Also change max Zs for B6 mcb to 6.18W)

143                                                     change “direct contact” for “basic protection fault”

144                                                     (change “indirect contact” for fault protection fault”

 

147                                                     bullet points to amend:

 

 

3rd      “Five second disconnection is mostly obsolete in domestic installations)

            Most circuits are now 0.4s disc. Except notably >32A cookers and showers!

 

7th      Delete this statement-it was listed in the original draft of the regulations