Technical

Contents

• Screwed immersion heater schematic
• Vat heater installation instructions
• Advice on PAT testing immersion heaters
• British Standard pipe thread sizes
• Screwed immersion heater schematic
• IEE wiring regulations
• British Standard pipe thread sizes

Screwed immersion heater schematic

Download a wiring diagram for our screwed immersion heaters by clicking here

Vat heater installation instructions

Point-by-point text instructions for installing and maintaining vat heaters can be downloaded by clicking here.

Tips on PAT testing of immersion heaters

Immersion heaters have to be treated differently from other appliances when PAT tested. You can download tips on this by clicking here.

How to install, wire, and maintain an immersion heater

Installation, Wiring and Maintenance Instructions are available here, as are the IEE Wiring Regulations.

Busbar selection

Download the Process Heating Services guide to busbar ratings.

IEE Wiring Regulations

Download a free colour guide to the 2004 IEE Wiring Regulations amending the British Standard to specify new cable core colours for all new fixed wiring in electrical installations in the UK by clicking here. These colours are referred to as “harmonised”, because they bring the UK standards more closely in line with practice in mainland Europe.

British Standard pipe thread sizes: parallel, BSPP/BPSF

Download this table to print out as an Adobe Acrobat PDF file.
Click on any heading to sort the table by that column.

British Standard pipe thread: parallel, BSPP/BPSF

nominal size	dash size	outer diameter/mm	inner diameter male thread/mm	pitch/mm	threads per inch	pitch diameter	thread height/mm	tap drill diameter/mm
1/8"	2	9.728	8.566	0.907	28	9.147	0.581	8.7
1/4"	4	13.157	11.445	1.337	19	12.301	0.856	11.6
3/8"	6	16.662	14.95	1.337	19	15.806	0.856	15
1/2"	8	20.955	18.631	1.814	14	19.793	1.162	19
5/8"	10	22.911	20.587	1.814	14	21.749	1.162	20.75
3/4"	12	26.441	24.117	1.814	14	25.279	1.162	24.5
7/8"	14	30.201	27.877	1.814	14	29.039	1.162	28
1"	16	33.249	30.291	2.309	11	31.77	1.479	30.5
1 1/8"	18	37.897	34.939	2.309	11	36.418	1.479	35
1 1/4"	20	41.91	38.952	2.309	11	40.431	1.479	39.5
1 3/8"	22	44.323	41.365	2.309	11	42.844	1.479	41.5
1 1/2"	24	47.803	44.845	2.309	11	46.324	1.479	45
1 3/4"	28	53.746	50.788	2.309	11	52.267	1.479	51
2"	32	59.614	56.656	2.309	11	58.135	1.479	57
2 1/4"	36	65.71	62.752	2.309	11	64.231	1.479	63
2 1/2"	40	75.184	72.226	2.309	11	73.705	1.479	72.5
2 3/4"	44	81.534	78.576	2.309	11	80.055	1.479	79
3"	48	87.884	84.926	2.309	11	86.405	1.479	85.5