SWA Armour

davel81 · Dec 19, 2012

Hi

Ive got to run in some SWA cables for some large bits of equipment. Its TP&N, is there any issues with using 4 core and using the armour for the earth (ensuring the Zs is ok)?

trev · Dec 19, 2012

There's a thread on here about this very subject and someone posted a table showing what was acceptable and what was not, so if you find it you'll know long before you do your Zs test.

telectrix · Dec 19, 2012

as long as the armour is of sufficient csa. generally all SWA up to 90mm complies. some of the xlpe SWA doesn't.

Brightspark2 · Dec 19, 2012

As long as the armour meets the requirements then theres no problem at all...

http://www.earthingnuts.co.uk/#

Have a look through table 5 under technical info...

bugsy · Dec 19, 2012

Lenny posted a sticky on this very subject

sjhall · Dec 19, 2012

Unless cost is massively different I'd always use 5 core.... here's a link for you to look at

http://www.gadsolutions.biz/component/k2/item/3-swa-as-cpc

Guest55 · Dec 19, 2012

davel81 said:
Hi

Ive got to run in some SWA cables for some large bits of equipment. Its TP&N, is there any issues with using 4 core and using the armour for the earth (ensuring the Zs is ok)?

more to the point , how "large" is large ? , in current rating.

davel81 · Dec 19, 2012

biff55 said:
more to the point , how "large" is large ? , in current rating.

about 30kw

Brightspark2 · Dec 19, 2012

bugsy said:
Lenny posted a sticky on this very subject

Is it still there?...had disappeared last time I looked...

Deleted member 26818 · Dec 19, 2012

Don't bother with that earthing nuts chart.
Do a search for 'john peckham' and use his chart.

Guest55 · Dec 19, 2012

davel81 said:
about 30kw

which is round about 43A per phase per machine without power factor or diversity.
so youre only going to use 10-16mm depending on length so xlpe will be fine for swa earthing

Engineer54 · Dec 19, 2012

Brightspark2 said:
As long as the armour meets the requirements then theres no problem at all...

Earthing Nuts - Speed up metal cable gland installation and EMI / RFI screening

Have a look through table 5 under technical info...

THROW THAT DAMMED TABLE AWAY!! It causes more confusion, than any help!!

Use this table where all the calculations have been done for you...

Blue = min CSA of cables SWA to comply.

(Red) = Cable does not comply.

Table for 70[SUP]0[/SUP]C Thermoplastic PVC SWA cables.

Conductor CSA	Minimum CSA of SWA to meet 54G	CSA of armour 2 core	CSA of armour 3 core	CSA of armour 4 core
1.5	3.4	15	16	17
2.5	5.7	17	19	20
4	9.0	21	23	35
6	13.6	24	36	40
10	22.6	41	44	49
16	36.1	46	50	72
25	36.1	60	66	76
35	36.1	66	74	84
50	56.4	74	84	122
70	79.0	84	119	138
95	107.2	122	138	160
120	135.3	(131)	150	220
150	169.2	(144)	211	240
185	208.6	(201)	230	265
240	270.6	(225)	(260)	299
300	338.3	(250)	(289)	(333)
400	403.9	(279)	(319)	467

Table for 90[SUP]0[/SUP]C Thermosetting SWA cables operating at 70[SUP]0[/SUP]C.

Conductor CSA	Minimum CSA of SWA to meet 54G	CSA of armour 2 core	CSA of armour 3 core	CSA of armour 4 core
1.5	3.4	16	17	18
2.5	5.7	17	19	20
4	9.0	19	21	23
6	13.6	22	23	36
10	22.6	26	39	43
16	36.1	41	44	49
25	36.1	42	62	70
35	36.1	62	70	80
50	56.4	68	78	90
70	79.0	80	90	131
95	107.2	113	128	147
120	135.3	(125)	141	206
150	169.2	(138)	201	230
185	208.6	(191)	220	255
240	270.6	(215)	(250)	289
300	338.3	(235)	(269)	(319)
400	451.0	(265)	(304)	452