Liebert UPS System Cable connections, Selection of signal cables, Power cables, Cabling layout

Chapter 3 Electrical Assemble

protective earth cable and lightning protection earth cable, should be 0.5 times of phase cable.

The relationship between the current and cross-sectional area is shown in Table 3- 2.

Table3-2 Recommended cross sectional area of cables

	20kVA		30kVA		40kVA		60kVA
Name
	Current	Cable	Current	Cable	Current	Cable	Current	Cable
	(A)	(mm2)	(A)	(mm2)	(A)	(mm2)	(A)	(mm2)
Battery	56	25	84	25	112	35	168	50
Bypass	37	16	56	16	74	25	112	35
Output	37	16	56	16	74	25	112	35
Input	44	16	66	16	88	25	132	35
Neutral line		25		25		35		50
Earth cable		16		16		25		25

3.1.3 Selection of signal cables

Signal cables should use shielded multi-conductor cables. But if cable with single conductor is used, the different cables should be bonded together to increase the mechanical strength. The number of the bonded cables should not exceed 30. The cross-sectional area of the cable with single conductor should be at least 0.5 sq-

mm.Serial communication cables should use 3 or 5 shielded conductor cables.

3.2Cable connections

3.2.1Power cables

1.Cabling layout

Cabling layout is shown in Figures 3-1 and 3-2. For single input UPS, the rectifier input and bypass input are connected together.

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